Abrasive articles and methods for forming same

ABSTRACT

An abrasive article can include a body including a first portion coupled to a second portion in a radial plane. The body can include a central opening extending in an axial direction of the body through the first portion and through the second portion. The central opening can include a circumferential surface defining an inner diameter of the body. The circumferential surface can be defined by at least a portion of the first portion and at least a portion of the second portion. The first portion can include first abrasive particles contained within a first bond material, including an inorganic material, and the second portion can include second abrasive particles contained within a second bond material, including an organic material. The organic material can include epoxy. In an embodiment, the second portion comprises an elongation-at-fracture of less than 2.7%, a Stiffness Value of at least 8.3, or a combination thereof.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application No. 63/216,838, entitled “ABRASIVE ARTICLES ANDMETHODS FOR FORMING SAME,” by Alexander NASHED et al., filed Jun. 30,2022, which is assigned to the current assignee hereof and incorporatedherein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present invention relates, in general, to abrasive articles, inparticular, to abrasive articles having a plurality of portions andmethods of forming the same.

DESCRIPTION OF THE RELATED ART

Abrasive articles are used in material removal operations, such ascutting, grinding, or shaping various materials. Fixed abrasive articlesinclude abrasive particles held in a bond material. The bond materialcan include an organic and/or inorganic material. The industry continuesto demand improved abrasive articles.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be better understood, and its numerousfeatures and advantages made apparent to those skilled in the art byreferencing the accompanying drawings.

FIG. 1 includes an illustration of a cross-section of the abrasive bodyof an abrasive article according to another embodiment.

FIG. 2 includes an illustration of the body of an exemplary abrasivearticle according to an embodiment.

FIG. 3A includes an illustration of a top-down view of a portion of thebody of FIG. 1 .

FIG. 3B includes an illustration of a top-down view of another portionof the body of FIG. 1 .

FIG. 4 includes an illustration of an abrasive particle according toanother embodiment.

FIG. 5A includes a perspective view illustration of a shaped abrasiveparticle in accordance with an embodiment.

FIG. 5B includes a cross-sectional illustration of the shaped abrasiveparticle of FIG. 5A.

FIG. 5C includes a side-view illustration of a shaped abrasive particleaccording to an embodiment.

FIGS. 6A and 6B include flowcharts illustrating a forming processaccording to an embodiment.

FIGS. 7A and 7B include plot illustrating storage modulus vs.temperature of abrasive samples.

FIG. 8 includes a scanning electron microscope image of an abrasivesample.

FIG. 9 includes an illustration of thermal expansion of abrasivesamples.

Skilled artisans appreciate that elements in the figures are illustratedfor simplicity and clarity and have not necessarily been drawn to scale.For example, the dimensions of some of the elements in the figures maybe exaggerated relative to other elements to help to improveunderstanding of embodiments of the invention.

DETAILED DESCRIPTION

The following description in combination with the figures is provided toassist in understanding the teachings provided herein. The followingdisclosure will focus on specific implementations and embodiments of theteachings. This focus is provided to assist in describing the teachingsand should not be interpreted as a limitation on the scope orapplicability of the teachings. However, other teachings can certainlybe used in this application.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having,” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a method,article, or apparatus that comprises a list of features is notnecessarily limited only to those features but may include otherfeatures not expressly listed or inherent to such method, article, orapparatus. Further, unless expressly stated to the contrary, “or” refersto an inclusive-or and not to an exclusive-or. For example, a conditionA or B is satisfied by any one of the following: A is true (or present),and B is false (or not present), A is false (or not present), and B istrue (or present), and both A and B are true (or present).

Also, the use of “a” or “an” is employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one, and the singular alsoincludes the plural, or vice versa, unless it is clear that it is meantotherwise. For example, when a single item is described herein, morethan one item may be used in place of a single item. Similarly, wheremore than one item is described herein, a single item may be substitutedfor that more than one item.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. The materials, methods, andexamples are illustrative only and not intended to be limiting. To theextent that certain details regarding specific materials and processingacts are not described, such details may include conventionalapproaches, which may be found in reference books and other sourceswithin the manufacturing arts.

Embodiments are directed to abrasive articles, including a bodyincluding a plurality of portions. In an aspect, the portions mayinclude a different abrasive characteristic. For example, the body mayinclude a first portion coupled to a second portion, in which the firstportion may be configured to conduct a coarse grinding operation, andthe second portion may be configured to conduct a fine grindingoperation. In a further aspect, the portions may include a differentcomposition. For example, the first portion may include abrasiveparticles contained in a bond material, including an inorganic material,and the second portion may include abrasive particles contained in abond material, including an organic material. The abrasive articles ofembodiments herein can have improved dimension and/or thermal stabilityin fast material-removal operations. In particular, the abrasive articlecan have improved fracture-at-elongation, Young's Modulus, hardness,stiffness, coefficient of thermal expansion, or any combination thereof.

Embodiments are drawn to methods of forming abrasive articles. Themethods may allow the formation of the body, including portionsincluding a homogenous distribution of abrasive particles in a bondmaterial. In particular embodiments, methods may include dispersing fineabrasive particles in a viscous bond material to form a uniform mixture,which facilitates formation of the abrasive articles having improvedperformance.

The abrasive articles of embodiments herein can include fixed abrasives,such as bonded abrasives. The abrasive body may have any suitable sizeand shape as known in the art and can be incorporated into various typesof abrasive articles to form an abrasive article suitable for conductingmaterial removal operations, including but not limited to abrasivewheels, cones, hones, cups, flanged-wheels, tapered cups, segments,mounted-point tools, discs, thin wheels, grinding wheels, large diametercut-off wheels, and the like. In a particular embodiment, the abrasivearticles can include abrasive wheels. In a more particular example, theabrasive articles may be suitable for gear grinding, which often demandsboth fast removal rates and the generation of precise surface features.

Referring to FIG. 1 , a cross-sectional view of the body 100 of anexemplary abrasive article is illustrated in accordance with anembodiment. The body 100 may take the form of a wheel, including acentral opening 110 extending in the direction of the longitudinal axis150. As illustrated, the longitudinal axis 150 extends in the axialdirection and perpendicularly through the radial plane 160. The body 100can include a first portion 101 and a second portion 102 that is coupledto the first portion 101 in the radial plane 160. In a particularembodiment, the first portion 101 can be bonded to the second portion102. An adhesive may be used to facilitate the bonding of the firstportion 101 to the second portion 102. An exemplary adhesive may includeepoxy, polyurethane, or the like.

The body 100 can include the circumferential surface 112 defining thecentral opening 110 and the inner diameter D_(I) of the body 100. Thecentral opening can extend through the first portion 101 and through thesecond portion 102. The outer peripheral surface 113 of the body 100 maydefine the outer diameter D_(O) of the body 100. The body may include atotal thickness t. The central opening 110 may extend through the entirethickness of the body 100.

As illustrated in FIG. 1 , the first portion 101 may include a thicknesst₁ extending for a portion of the total thickness t, and the secondportion 102 may include a thickness t₂ extending for another portion ofthe total thickness t. As illustrated, t₁+t₂=t. It will be appreciatedthat the body of embodiments herein may include one or more additionalportions, such as a third portion, coupled to the first and secondportions 101 and 102, and a total of the thickness of each of theportions may make up the total thickness t of the body.

The first portion 101 can include a peripheral region 111 and a centralregion 121 that are coaxial and coupled in the axial direction. Inparticular embodiments, the peripheral region 111 can be bonded to thecentral region 121 directly or indirectly. In an example, the peripheralregion 111 may be sinter-bonded to the central region. In anotherexample, an adhesive may be used to facilitate the bonding between theperipheral region 111 and the central region 121, and an exemplaryadhesive may include epoxy, polyurethane, or the like.

The first portion 101 can include an inner circumferential surface 141and outer peripheral surface 131. As illustrated, the innercircumferential surface 141 may define a portion of the circumferentialsurface 112 of the body 100, and the outer peripheral surface 131 maydefine a portion of the outer peripheral surface 113.

The second portion 102 can include an inner circumferential surface 142and an outer peripheral surface 141. The inner circumferential surface142 may define a portion of the circumferential surface 112 of the body100, and the outer peripheral surface 141 may define a portion of theouter peripheral surface 113.

In an embodiment, the outer peripheral surface 113 of the body 100 canbe profiled. For example, the outer peripheral surface 113 can includesurface features to facilitate a material removal operation on aworkpiece. In particular, the surface features can be complimentary tothe surface features of the workpiece. In an embodiment, the surfacefeatures can include geometric features. In further embodiments, thesurface features may include threads, a particular roughness, or thelike to facilitate material removal operations on workpieces.

Briefly turning to FIG. 2 , a cross-sectional view of the body 200 ofanother exemplary abrasive article is illustrated. The body 200 caninclude a first portion 201 and a second portion 202 and be similar tothe body 100 illustrated in FIG. 1 , except that the outer peripheralsurface 253 can include surface features, such as geometric features,263. In another embodiment, surface features, such as geometric features263 or another feature, may be disposed on the circumferential surfaceof the body. For instance, the circumference surface 262 instead of theouter peripheral surface 253 may include the surface features 263.

FIG. 3A includes an illustration of the top-down view of the firstportion 101 of the body 100 illustrated in FIG. 1 , including theperipheral region 111 and the central region 121. In an embodiment, thefirst portion can include first abrasive particles contained in a firstbond material.

In an embodiment, the first abrasive particles may include a materialincluding an oxide, carbide, nitride, boride, oxycarbide, oxynitrides,silicate, oxyboride, superabrasives, minerals, or any combinationthereof. For example, the first abrasive particles may include silicondioxide, silicon carbide, alumina, zirconia, rare earth-containingmaterials, cerium oxide, sol-gel derived particles, iron oxide, gypsum,glass-containing particles, or a combination thereof. In a particularembodiment, the first abrasive particles may include an oxide, includingan alumina-based material. For example, the first abrasive particles mayinclude fused alumina, sol-gel alumina, sintered alumina,microcrystalline alumina, nanocrystalline alumina, sintered alumina withadditives, shaped and sintered aluminum oxide, seeded alumina, pinkalumina, ruby alumina, electrofused monocrystalline alumina,standard-ceramic alumina, alumina-zirconia, extruded bauxite, extrudedalumina, or any combination thereof. In a particular example, the firstabrasive particles may include seeded gel alumina particles.

In an embodiment, at least a portion of the first abrasive particles caninclude alpha-alumina having a particular average crystallite size. Inan aspect, the first abrasive particles can include particles havingalpha-alumina having an average crystallite size of at least 0.1microns, at least 0.12 microns, at least 0.15 microns, or at least 0.17microns. In another aspect, the average crystallite size may be at most0.5 microns, such as at most 0.4 microns, at most 0.3 microns, or atmost 0.2 microns. In another example, the first abrasive particles mayinclude particles including alpha-alumina having an average crystallitesize in a range including any of the minimum and maximum values notedherein.

In a further embodiment, the first abrasive particles may includeparticles including an alumina-based material, including at least 50 wt% of alumina for the total weight of the particles. For example, theparticles may include at least 60 wt %, at least 70 wt %, at least 80 wt%, at least 90 wt %, at least 95 wt %, at least 96 wt %, at least 97 wt%, or at least 98 wt % of alumina for the total weight of the particles.In another example, the first abrasive particles may include particlesincluding at most 99.9 wt % of alumina for the total weight of theparticles, such as at most 99.5%, at most 99 wt %, or at most 98.5 wt %for the total weight of the particles. Moreover, the first abrasiveparticles can include particles including alumina in a content includingany of the minimum and maximum percentages noted herein. In particularexamples, the first abrasive particles can include alumina abrasiveparticles that consist essentially of alumina. In another particularexample, the first abrasive particles can consist essentially ofalumina. For example, the first abrasive particles may include at least95 wt % of alumina for the total weight of the first abrasive particles,such as at least 96 wt % or at least 97 wt % or at least 98.5 wt % ofalumina for the total weight of the first abrasive particles.

In an embodiment, the first abrasive particles may include one or moreoxide of one or more elements from alkaline earth, rare earth, atransition metal, or any combination thereof. For example, the firstabrasive particles may include a minor content of magnesia (MgO),zirconia (ZrO₂), titania (TiO₂), or any combination thereof. In aparticular example, the total content of oxides other than alumina maybe less than 50 wt % of the total weight of the first abrasiveparticles, such as at most 30 wt %, at most 20 wt %, at most 10 wt %, atmost 5 wt %, at most 3 wt %, at most 1 wt %, or at most 0.5 wt %.

In another embodiment, the first abrasive particles may include a blendof abrasive particles. In an aspect, the first abrasive particles mayinclude seeded alumina particles and fused alumina particles. In aparticular aspect, the first abrasive particles may include aluminaparticles, including a particular content of chromium oxide. Forinstance, the alumina particles may include at least 0.3 wt % ofchromium oxide for a total weight of the alumina abrasive particles,such as at least 0.5 wt %, at least 0.7 wt %, at least 1 wt %, at least1.2 wt %, at least 1.3 wt %, or at least 1.4 wt % for a total weight ofthe first abrasive particles. In another example, the first abrasiveparticles may include alumina particles, including at most 5.0 wt % ofchromium oxide for a total weight of the alumina abrasive particles,such as at most 4.5 wt %, at most 4.0 wt %, at most 3.5 wt %, at most3.0 wt %, at most 2.5 wt %, at most 2.3 wt %, at most 2 wt %, at most1.9 wt %, at most 1.8 wt %, at most 1.7 wt %, or at most 1.6 wt % for atotal weight of the alumina abrasive particles. Moreover, the firstabrasive particles may include alumina particles, including a content ofchromium oxide in a range including any of the minimum and maximumpercentages noted herein. In an even more particular aspect, the firstabrasive particles may include seeded alumina particles and fusedalumina particles including a content of chromium oxide noted herein.

In an embodiment, the first abrasive particles may include agglomeratedabrasive particles, unagglomerated abrasive particles, shaped abrasiveparticles, non-shaped abrasive particles, or any combination thereof.

In an embodiment, the first portion may include elongated abrasiveparticles. In an aspect, the elongated particles may include seededalumina. In another aspect, the elongated particles may include alphaalumina having the average crystallite size noted in embodiments herein.

In another aspect, the first abrasive particles may include elongatedabrasive particles having a particular average aspect ratio of length tocross-sectional width that can facilitate improved structure and/orperformance of the abrasive article. It is to be appreciated thatcross-sectional width can include diameter. Referring to FIG. 4 , anexemplary elongated abrasive particle 400 is illustrated, including across-sectional width or diameter W and a length L. In an aspect, thefirst abrasive particles may include elongated particles having anaverage aspect ratio of length to cross-sectional width of at least 1.2,such as at least 1.5, at least 2, at least 2.3, at least 2.5, at least2.8, at least 3, at least 4, at least 5, at least 6, at least 7, or atleast 8. In another aspect, the average aspect ratio may be at most 30,at most 20, at most 15, at most 12, at most 10, at most 9, at most 8, atmost 7, at most 6, at most 5, at most 4, or at most 3. Moreover, thefirst abrasive particles may include elongated abrasive particles havingan aspect ratio of length to cross-sectional width in a range includingany of the minimum and maximum values noted herein.

In an embodiment, the first abrasive particles can include elongatedabrasive particles having a particular average cross-sectional widththat can facilitate improved structure and/or performance of theabrasive article. In an aspect, the average cross-sectional width of atleast 5 microns, such as at least 10 microns, at least 20 microns, atleast 30 microns, at least 40 microns, at least 50 microns, at least 60microns, at least 70 microns, at least 80 microns, at least 90 microns,at least 100 microns, at least 110 microns, at least 120 microns, atleast 130 microns, at least 140 microns, at least 150 microns, at least160 microns, at least 180 microns, or at least 200 microns. The averagecross-sectional width of the elongated abrasive particles may bedetermined by using tiers of sieves to sieve the particles.

In another aspect, the first abrasive particles can include theelongated particles having an average cross-sectional width of at most2000 microns, such as at most 1800 microns, at most 1500 microns, atmost 1200 microns, at most 1100 microns, at most 1000 microns, at most900 microns, at most 800 microns, at most 700 microns, at most 500microns, at most 400 microns, at most 350 microns, at most 290 microns,at most 280 microns, at most 275 microns, at most 260 microns, at most250 microns, at most 240 microns, at most 230 microns, at most 220microns, at most 210 microns, at most 200 microns, at most 190 microns,at most 180 microns, at most 170 microns, at most 165 microns, at most160 microns, at most 150 microns, at most 140 microns, at most 130microns, at most 120 microns, at most 110 microns, at most 100 microns,at most 90 microns, at most 80 microns, at most 70 microns, at most 60microns, or at most 50 microns. Moreover, the average cross-sectionalwidth of the elongated abrasive particles can be in a range includingany of the minimum and maximum values noted above. For instance, theaverage cross-sectional width of the elongated abrasive particles can bein a range including at least 20 microns and at most 2000 microns or ina range including at least 100 microns and at most 1200 microns.

In a particular aspect, the first abrasive particles may consistessentially of the elongated particles.

In another aspect, the first abrasive particles may include granuleabrasive particles. In an example, the first abrasive particles mayinclude granule abrasive particles having an average particle size of atmost 500 microns, at most 450 microns, at most 400 microns, at most 380microns, at most 350 microns, at most 320 microns, at most 300 microns,at most 280 microns, at most 260 microns, at most 255 microns, at most250 microns, at most 240 microns, at most 230 microns, at most 210microns, at most 200 microns, at most 180 microns, at most 160 microns,at most 150 microns, at most 130 microns, at most 120 microns, at most110 microns, at most 100 microns, or at most 90 microns. In anotheraspect, the average particle size of the granule abrasive particles maybe at least 40 microns, at least 50 microns, at least 60 microns, suchas at least 80 microns, at least 90 microns, at least 100 microns, atleast 110 microns, at least 120 microns, at least 140 microns, at least150 microns, at least 170 microns, at least 180 microns, at least 190microns, at least 200 microns, at least 210 microns, at least 230microns, or at least 250 microns. Moreover, the average particle size ofthe granule abrasive particles can be in a range including any of theminimum and maximum values noted herein.

In an aspect, the first abrasive particles may consist essentially ofgranule abrasive particles. In a further aspect, the first abrasiveparticles may include the elongated abrasive particles and granuleabrasive particles. In a particular aspect, the first abrasive particlesmay include the elongated abrasive particles, including seeded aluminaand granule abrasive particles, including fused alumina or sinteredalumina or any combination thereof. In another particular aspect, thefirst abrasive particles may include elongated particles andagglomerated granule particles. In a particular example, the firstabrasive particles may consist essentially of elongated particles,agglomerated granule abrasive particles, or a combination thereof.

In an embodiment, at least a portion of the first abrasive particles mayinclude shaped abrasive particles.

The shaped abrasive particles can have various shapes. In general, theshaped abrasive particles may have a shape similar to shaping componentsused in the forming process. For example, a shaped abrasive particle mayhave a predetermined two-dimensional shape as viewed in any twodimensions of the three-dimension shape, and particularly in a dimensiondefined by the length and width of the particle. Some exemplarytwo-dimensional shapes can include a polygon, an ellipsoid, a numeral, aGreek alphabet letter, a Latin alphabet letter, a Russian alphabetcharacter, a Kanji character, a complex shape including a combination ofpolygonal shapes, and a combination thereof. In particular instances,the shaped abrasive particle may have a two-dimensional polygonal shapesuch as a triangle, a rectangle, a quadrilateral, a pentagon, a hexagon,a heptagon, an octagon, a nonagon, a decagon, and a combination thereof.

In one particular aspect, the shaped abrasive particles may be formed tohave a shape as illustrated in FIG. 5A. FIG. 5A includes a perspectiveview illustration of a shaped abrasive particle in accordance with anembodiment. Additionally, FIG. 5B includes a cross-sectionalillustration of the shaped abrasive particle of FIG. 5A. The body 801includes an upper surface 803 and a bottom surface 804 opposite theupper surface 803. The upper surface 803 and the bottom surface 804 canbe separated from each other by side surfaces 805, 806, and 807. Asillustrated, the body 801 of the shaped abrasive particle 800 can have agenerally triangular shape as viewed in a plane defined by the uppersurface 803. In particular, the body 801 can have a length (Lmiddle) asshown in FIG. 5B, which may be measured at the bottom surface 804 of thebody 801 and extending from a corner at the bottom surface correspondingto corner 813 at the top surface through a midpoint 881 of the body 801to a midpoint at the opposite edge of the body corresponding to the edge814 at the upper surface of the body. Alternatively, the body can bedefined by a second length or profile length (Lp), which is the measureof the dimension of the body from a side view at the upper surface 803or from a first corner 813 to an adjacent corner 812. Notably, thedimension of Lmiddle can be a length defining a distance between aheight at a corner (hc) and a height at a midpoint edge (hm) oppositethe corner. The dimension Lp can be a profile length along a side of theparticle defining the distance between h1 and h2 (as explained herein).Reference herein to the length can be a reference to either Lmiddle orLp.

The body 801 can further include a width (w) that is the longestdimension of the body and extending along a side. The shaped abrasiveparticle can further include a height (h), which may be a dimension ofthe shaped abrasive particle extending in a direction perpendicular tothe length and width in a direction defined by a side surface of thebody 801. Notably, as will be described in more detail herein, the body801 can be defined by various heights depending upon the location of thebody. In specific instances, the width can be greater than or equal tothe length, the length can be greater than or equal to the height, andthe width can be greater than or equal to the height.

Moreover, reference herein to any dimensional characteristic (e.g., h1,h2, hi, w, Lmiddle, Lp, and the like) can be a reference to a dimensionof a single particle of a batch. Alternatively, any reference to any ofthe dimensional characteristics can refer to a median value or anaverage value derived from the analysis of a suitable sampling ofparticles from a batch. Unless stated explicitly, reference herein to adimensional characteristic can be considered reference to a median valuethat is based on a statistically significant value derived from a samplesize of a suitable number of particles of a batch. Notably, for certainembodiments herein, the sample size can include at least 40 randomlyselected particles from a batch of particles. A batch of particles maybe a group of particles that are collected from a single process run,and more particularly, may include an amount of shaped abrasiveparticles suitable for forming a commercial-grade abrasive product, suchas at least about 20 lbs. of particles.

In accordance with an embodiment, the body 801 of the shaped abrasiveparticle can have a first corner height (hc) at a first region of thebody defined by a corner 813. Notably, the corner 813 may represent thepoint of greatest height on the body 801, however, the height at thecorner 813 does not necessarily represent the point of greatest heighton the body 801. The corner 813 can be defined as a point or region onthe body 301 defined by the joining of the upper surface 803, and twoside surfaces 805 and 807. The body 801 may further include othercorners, spaced apart from each other, including for example, corner 811and corner 812. As further illustrated, the body 801 can include edges814, 815, and 816 that can separated from each other by the corners 811,812, and 813. The edge 814 can be defined by an intersection of theupper surface 803 with the side surface 806. The edge 815 can be definedby an intersection of the upper surface 803 and side surface 805 betweencorners 811 and 813. The edge 816 can be defined by an intersection ofthe upper surface 803 and side surface 807 between corners 812 and 813.

As further illustrated, the body 801 can include a second midpointheight (hm) at a second end of the body 801, which can be defined by aregion at the midpoint of the edge 814, which can be opposite the firstend defined by the corner 813. The axis 850 can extend between the twoends of the body 801. FIG. 5B is a cross-sectional illustration of thebody 801 along the axis 850, which can extend through a midpoint 881 ofthe body 801 along the dimension of length (Lmiddle) between the corner813 and the midpoint of the edge 814.

In accordance with an embodiment, the shaped abrasive particles of theembodiments herein, including for example, the particles of FIGS. 5A and5B can have an average difference in height, which is a measure of thedifference between hc and hm. For convention herein, the averagedifference in height will be generally identified as hc−hm, however, itis defined as an absolute value of the difference, and it will beappreciated that the average difference in height may be calculated ashm-hc when the height of the body 801 at the midpoint of the edge 814 isgreater than the height at the corner 813. More particularly, theaverage difference in height can be calculated based upon a plurality ofshaped abrasive particles from a suitable sample size, such as at least40 particles from a batch as defined herein. The heights hc and hm ofthe particles can be measured using a STIL (Sciences et TechniquesIndustrielles de la Lumiere—France) Micro Measure 3D SurfaceProfilometer (white light (LED) chromatic aberration technique), and theaverage difference in height can be calculated based on the averagevalues of hc and hm from the sample.

As illustrated in FIG. 5B, in one particular embodiment, the body 801 ofthe shaped abrasive particle may have an average difference in height atdifferent locations at the body. The body can have an average differencein height, which can be the absolute value of [hc−hm] between the firstcorner height (hc) and the second midpoint height (hm) is at least about20 microns. It will be appreciated that the average difference in heightmay be calculated as hm−hc when the height of the body 801 at a midpointof the edge is greater than the height at an opposite corner. In otherinstances, the average difference in height [hc−hm] can be at leastabout 25 microns, at least about 30 microns, at least about 36 microns,at least about 40 microns, at least about 60 microns, such as at leastabout 65 microns, at least about 70 microns, at least about 75 microns,at least about 80 microns, at least about 90 microns, or even at leastabout 100 microns. In one non-limiting embodiment, the averagedifference in height can be not greater than about 300 microns, such asnot greater than about 250 microns, not greater than about 220 microns,or even not greater than about 180 microns. It will be appreciated thatthe average difference in height can be within a range between any ofthe minimum and maximum values noted above.

Moreover, it will be appreciated that the average difference in heightcan be based upon an average value of hc. For example, the averageheight of the body at the corners (Ahc) can be calculated by measuringthe height of the body at all corners and averaging the values, and maybe distinct from a single value of height at one corner (hc).Accordingly, the average difference in height may be given by theabsolute value of the equation [Ahc−hi], wherein hi is the interiorheight which can be the smallest dimension of the height of the body asmeasured along a dimension between any corner and opposite midpoint edgeon the body. Furthermore, it will be appreciated that the averagedifference in height can be calculated using a median interior height(Mhi) calculated from a suitable sample size of a batch of shapedabrasive particles and an average height at the corners for allparticles in the sample size. Accordingly, the average difference inheight may be given by the absolute value of the equation [Ahc−Mhi].

In particular instances, the body 801 can be formed to have a primaryaspect ratio, which is a ratio expressed as width:length, wherein thelength may be Lmiddle, having a value of at least 1:1. In otherinstances, the body can be formed such that the primary aspect ratio(w:l) is at least about 1.5:1, such as at least about 2:1, at leastabout 4:1, or even at least about 5:1. Still, in other instances, theabrasive particle can be formed such that the body has a primary aspectratio that is not greater than about 10:1, such as not greater than 9:1,not greater than about 8:1, or even not greater than about 5:1. It willbe appreciated that the body 801 can have a primary aspect ratio withina range between any of the ratios noted above. Furthermore, it will beappreciated that reference herein to a height is the maximum heightmeasurable of the abrasive particle. It will be described later that theabrasive particle may have different heights at different positionswithin the body 801.

In addition to the primary aspect ratio, the abrasive particle can beformed such that the body 801 comprises a secondary aspect ratio, whichcan be defined as a ratio of length:height, wherein the length may beLmiddle, and the height is an interior height (hi). In certaininstances, the secondary aspect ratio can be within a range betweenabout 5:1 and about 1:3, such as between about 4:1 and about 1:2, oreven between about 3:1 and about 1:2. It will be appreciated that thesame ratio may be measured using median values (e.g., median length andinterior median height) for a batch of particles.

In accordance with another embodiment, the abrasive particle can beformed such that the body 801 comprises a tertiary aspect ratio, definedby the ratio width:height, wherein the height is an interior height(hi). The tertiary aspect ratio of the body 801 can be within a rangebetween about 10:1 and about 1.5:1, such as between 8:1 and about 1.5:1,such as between about 6:1 and about 1.5:1, or even between about 4:1 andabout 1.5:1. It will be appreciated that the same ratio may be measuredusing median values (e.g., median length, median middle length, and/orinterior median height) for a batch of particles.

According to one embodiment, the body 801 of the shaped abrasiveparticle can have particular dimensions, which may facilitate improvedperformance. For example, in one instance, the body can have an interiorheight (hi), which can be the smallest dimension of the height of thebody as measured along a dimension between any corner and oppositemidpoint edge on the body. In particular instances, wherein the body isa generally triangular two-dimensional shape, the interior height (hi)may be the smallest dimension of height (i.e., measure between thebottom surface 804 and the upper surface 805) of the body for threemeasurements taken between each of the three corners and the oppositemidpoint edges. The interior height (hi) of the body of a shapedabrasive particle is illustrated in FIG. 5B. According to oneembodiment, the interior height (hi) can be at least about 28% of thewidth (w). The height (hi) of any particle may be measured by sectioningor mounting and grinding the shaped abrasive particle and viewing in amanner sufficient (e.g., light microscope or SEM) to determine thesmallest height (hi) within the interior of the body 801. In oneparticular embodiment, the height (hi) can be at least about 29% of thewidth, such as at least about 30%, or even at least about 33% of thewidth of the body. For one non-limiting embodiment, the height (hi) ofthe body can be not greater than about 80% of the width, such as notgreater than about 76%, not greater than about 73%, not greater thanabout 70%, not greater than about 68% of the width, not greater thanabout 56% of the width, not greater than about 48% of the width, or evennot greater than about 40% of the width. It will be appreciated that theheight (hi) of the body can be within a range between any of theabove-noted minimum and maximum percentages.

A batch of shaped abrasive particles can be fabricated, wherein themedian interior height value (Mhi) can be controlled, which mayfacilitate improved performance. In particular, the median internalheight (hi) of a batch can be related to a median width of the shapedabrasive particles of the batch in the same manner as described above.Notably, the median interior height (Mhi) can be at least about 28%,such as at least about 29%, at least about 30%, or even at least about33% of the median width of the shaped abrasive particles of the batch.For one non-limiting embodiment, the median interior height (Mhi) of thebody can be not greater than about 80%, such as not greater than about76%, not greater than about 73%, not greater than about 70%, not greaterthan about 68% of the width, not greater than about 56% of the width,not greater than about 48% of the width, or even not greater than about40% of the median width. It will be appreciated that the median interiorheight (Mhi) of the body can be within a range between any of theabove-noted minimum and maximum percentages.

Furthermore, the batch of shaped abrasive particles may exhibit improveddimensional uniformity as measured by the standard deviation of adimensional characteristic from a suitable sample size. According to oneembodiment, the shaped abrasive particles can have an interior heightvariation (Vhi), which can be calculated as the standard deviation ofinterior height (hi) for a suitable sample size of particles from abatch. According to one embodiment, the interior height variation can benot greater than about 60 microns, such as not greater than about 58microns, not greater than about 56 microns, or even not greater thanabout 54 microns. In one non-limiting embodiment, the interior heightvariation (Vhi) can be at least about 2 microns. It will be appreciatedthat the interior height variation of the body can be within a rangebetween any of the above-noted minimum and maximum values.

For another embodiment, the body of the shaped abrasive particle canhave an interior height (hi) of at least about 400 microns. Moreparticularly, the height may be at least about 450 microns, such as atleast about 475 microns, or even at least about 500 microns. In stillone non-limiting embodiment, the height of the body can be not greaterthan about 3 mm, such as not greater than about 2 mm, not greater thanabout 1.5 mm, not greater than about 1 mm, or not greater than about 800microns. It will be appreciated that the height of the body can bewithin a range between any of the above-noted minimum and maximumvalues. Moreover, it will be appreciated that the above range of valuescan be representative of a median interior height (Mhi) value for abatch of shaped abrasive particles.

For certain embodiments herein, the body of the shaped abrasive particlecan have particular dimensions, including, for example, a width≥length,a length≥height, and a width≥height. More particularly, the body 801 ofthe shaped abrasive particle can have a width (w) of at least about 600microns, such as at least about 700 microns, at least about 800 microns,or even at least about 900 microns. In one non-limiting instance, thebody can have a width of not greater than about 4 mm, such as notgreater than about 3 mm, not greater than about 2.5 mm, or even notgreater than about 2 mm. It will be appreciated that the width of thebody can be within a range between any of the above-noted minimum andmaximum values. Moreover, it will be appreciated that the above range ofvalues can be representative of a median width (Mw) for a batch ofshaped abrasive particles.

The body 801 of the shaped abrasive particle can have particulardimensions, including, for example, a length (L middle or Lp) of atleast about 0.4 mm, such as at least about 0.6 mm, at least about 0.8mm, or even at least about 0.9 mm. Still, for at least one non-limitingembodiment, the body 801 can have a length of not greater than about 4mm, such as not greater than about 3 mm, not greater than about 2.5 mm,or even not greater than about 2 mm. It will be appreciated that thelength of the body 801 can be within a range between any of theabove-noted minimum and maximum values. Moreover, it will be appreciatedthat the above range of values can be representative of a median length(Ml), which may be more particularly, a median middle length (MLmiddle)or median profile length (MLp) for a batch of shaped abrasive particles.

The shaped abrasive particle can have a body 801 having a particularamount of dishing, wherein the dishing value (d) can be defined as aratio between an average height of the body 801 at the corners (Ahc) ascompared to the smallest dimension of the height of the body at theinterior (hi). The average height of the body 801 at the corners (Ahc)can be calculated by measuring the height of the body at all corners andaveraging the values and may be distinct from a single value of heightat one corner (hc). The average height of the body 801 at the corners orat the interior can be measured using a STIL (Sciences et TechniquesIndustrielles de la Lumiere—France) Micro Measure 3D SurfaceProfilometer (white light (LED) chromatic aberration technique).Alternatively, the dishing may be based upon a median height of theparticles at the corner (Mhc) calculated from a suitable sampling ofparticles from a batch. Likewise, the interior height (hi) can be amedian interior height (Mhi) derived from a suitable sampling of shapedabrasive particles from a batch. According to one embodiment, thedishing value (d) can be not greater than about 2, such as not greaterthan about 1.9, not greater than about 1.8, not greater than about 1.7,not greater than about 1.6, or even not greater than about 1.5. Still,in at least one non-limiting embodiment, the dishing value (d) can be atleast about 0.9, such as at least about 1.0. It will be appreciated thatthe dishing ratio can be within a range between any of the minimum andmaximum values noted above. Moreover, it will be appreciated that theabove dishing values can be representative of a median dishing value(Md) for a batch of shaped abrasive particles.

The shaped abrasive particles of the embodiments herein, including forexample, the body 801 of the particle of FIG. 5A, can have a bottomsurface 804 defining a bottom area (A_(b)). In particular instances, thebottom surface 304 can be the largest surface of the body 801. Thebottom surface can have a surface area defined as the bottom area(A_(b)) that is greater than the surface area of the upper surface 803.Additionally, the body 801 can have a cross-sectional midpoint area(A_(m)), defining an area of a plane perpendicular to the bottom areaand extending through a midpoint 881 (a between the top and bottomsurfaces) of the particle. In certain instances, the body 801 can havean area ratio of bottom area to midpoint area (A_(b)/A_(m)) of notgreater than about 6. In more particular instances, the area ratio canbe not greater than about 5.5, such as not greater than about 5, notgreater than about 4.5, not greater than about 4, not greater than about3.5, or even not greater than about 3. Still, in one non-limitingembodiment, the area ratio may be at least about 1.1, such as at leastabout 1.3, or even at least about 1.8. It will be appreciated that thearea ratio can be within a range between any of the minimum and maximumvalues noted above. Moreover, it will be appreciated that the above arearatios can be representative of a median area ratio for a batch ofshaped abrasive particles.

Furthermore, the shaped abrasive particles of the embodiments herein,including, for example, the particle of FIG. 5B can have a normalizedheight difference of at least about 0.3. The normalized heightdifference can be defined by the absolute value of the equation[(hc-hm)/(hi)]. In other embodiments, the normalized height differencecan be not greater than about 0.26, such as not greater than about 0.22,or even not greater than about 0.19. Still, in one particularembodiment, the normalized height difference can be at least about 0.04,such as at least about 0.05, at least about 0.06. It will be appreciatedthat the normalized height difference can be within a range between anyof the minimum and maximum values noted above. Moreover, it will beappreciated that the normalized height values mentioned above can berepresentative of a median normalized height value for a batch of shapedabrasive particles.

In another instance, the body 801 can have a profile ratio of at leastabout 0.04, wherein the profile ratio is defined as a ratio of theaverage difference in height [hc−hm] to the length (Lmiddle) of theshaped abrasive particle, defined as the absolute value of[(hc−hm)/(Lmiddle)]. It will be appreciated that the length (Lmiddle) ofthe body can be the distance across the body 801 as illustrated in FIG.5B. Moreover, the length may be an average or median length calculatedfrom a suitable sampling of particles from a batch of shaped abrasiveparticles as defined herein. According to a particular embodiment, theprofile ratio can be at least about 0.05, at least about 0.06, at leastabout 0.07, at least about 0.08, or even at least about 0.09. Still, inone non-limiting embodiment, the profile ratio can be not greater thanabout 0.3, such as not greater than about 0.2, not greater than about0.18, not greater than about 0.16, or even not greater than about 0.14.It will be appreciated that the profile ratio can be within a rangebetween any of the minimum and maximum values noted above. Moreover, itwill be appreciated that the above profile ratio can be representativeof a median profile ratio for a batch of shaped abrasive particles.

According to another embodiment, the body 801 can have a particular rakeangle, which may be defined as an angle between the bottom surface 804and a side surface 805, 806, or 807 of the body. For example, the rakeangle may be within a range between about 1° and about 80°. For otherparticles herein, the rake angle can be within a range between about 5°and 55°, such as between about 10° and about 50°, between about 15° and50°, or even between about 20° and 50°. The formation of an abrasiveparticle having such a rake angle can improve the abrading capabilitiesof the abrasive particle. Notably, the rake angle can be within a rangebetween any two rake angles noted above.

According to another embodiment, the shaped abrasive particles herein,including, for example, the particles of FIGS. 5A and 5B can have anellipsoidal region 817 in the upper surface 803 of the body 801. Theellipsoidal region 817 can be defined by a trench region 818 that canextend around the upper surface 803 and define the ellipsoidal region817. The ellipsoidal region 817 can encompass the midpoint 881.Moreover, it is thought that the ellipsoidal region 817 defined in theupper surface can be an artifact of the forming process and may beformed as a result of the stresses imposed on the mixture during theformation of the shaped abrasive particles according to the methodsdescribed herein.

The shaped abrasive particle can be formed such that the body includes acrystalline material, and more particularly, a polycrystalline material.Notably, the polycrystalline material can include abrasive grains. Inone embodiment, the body can be essentially free of organic material,including, for example, a binder. More particularly, the body canconsist essentially of a polycrystalline material.

In one aspect, the body of the shaped abrasive particle can be anagglomerate, including a plurality of abrasive particles, grit, and/orgrains bonded to each other to form the body 801 of the abrasiveparticle 800. Suitable abrasive grains can include nitrides, oxides,carbides, borides, oxynitrides, oxyborides, diamond, superabrasives(e.g., cBN), and a combination thereof. In particular instances, theabrasive grains can include an oxide compound or complex, such asaluminum oxide, zirconium oxide, titanium oxide, yttrium oxide, chromiumoxide, strontium oxide, silicon oxide, and a combination thereof. In oneparticular instance, the abrasive particle 800 is formed such that theabrasive grains forming the body 800 include alumina, and moreparticularly, may consist essentially of alumina. In an alternativeembodiment, the shaped abrasive particles can include geosets, includingfor example, polycrystalline compacts of abrasive or superabrasivematerials including a binder phase, which may include a metal, metalalloy, super alloy, cermet, and a combination thereof. Some exemplarybinder materials can include cobalt, tungsten, and a combinationthereof.

The abrasive grains (i.e., crystallites) contained within the body mayhave an average grain size that is generally not greater than about 100microns. In other embodiments, the average grain size can be less, suchas not greater than about 80 microns, not greater than about 50 microns,not greater than about 30 microns, not greater than about 20 microns,not greater than about 10 microns, or even not greater than about 1micron. Still, the average grain size of the abrasive grains containedwithin the body can be at least about 0.01 microns, such as at leastabout 0.05 microns, such as at least about 0.08 microns, at least about0.1 microns, or even at least about 1 micron. It will be appreciatedthat the abrasive grains can have an average grain size within a rangebetween any of the minimum and maximum values noted above.

In accordance with certain embodiments, the abrasive particle can be acomposite article, including at least two different types of abrasivegrains within the body. It will be appreciated that different types ofabrasive grains are abrasive grains having different compositions withregard to each other. For example, the body can be formed such that itincludes at least two different types of abrasive grains, wherein thetwo different types of abrasive grains can be nitrides, oxides,carbides, borides, oxynitrides, oxyborides, diamond, and a combinationthereof.

In accordance with an embodiment, the abrasive particle 800 can have anaverage particle size, as measured by the largest dimension measurableon the body 801, of at least 100 microns. In fact, the abrasive particle800 can have an average particle size of at least 150 microns, such asat least 200 microns, at least 300 microns, at least 400 microns, atleast 500 microns, at least 600 microns, at least 700 microns, at least800 microns, or even at least 900 microns. Still, the abrasive particle800 can have an average particle size that is not greater than 5 mm,such as not greater than 3 mm, not greater than 2 mm, or even notgreater than 1.5 mm. It will be appreciated that the abrasive particle100 can have an average particle size within a range between any of theminimum and maximum values noted above.

The shaped abrasive particles of the embodiments herein can have apercent flashing that may facilitate improved performance. Notably, theflashing defines an area of the particle as viewed along one side, suchas illustrated in FIG. 6C, wherein the flashing extends from a sidesurface of the body within the boxes 888 and 889. The flashing canrepresent tapered regions proximate to the upper surface and bottomsurface of the body. The flashing can be measured as the percentage ofthe area of the body along the side surface contained within a boxextending between an innermost point of the side surface (e.g., 891) andan outermost point (e.g., 892) on the side surface of the body. In oneparticular instance, the body can have a particular content of flashing,which can be the percentage of the area of the body contained within theboxes 888 and 889 compared to the total area of the body containedwithin boxes 888, 889, and 890. According to one embodiment, the percentflashing (f) of the body can be at least about 10%. In anotherembodiment, the percent flashing can be greater, such as at least about12%, such as at least about 14%, at least about 16%, at least about 18%,or even at least about 20%. Still, in a non-limiting embodiment, thepercent flashing of the body can be controlled and may be not greaterthan about 45%, such as not greater than about 40%, or even not greaterthan about 36%. It will be appreciated that the percent flashing of thebody can be within a range between any of the above minimum and maximumpercentages. Moreover, it will be appreciated that the above flashingpercentages can be representative of an average flashing percentage or amedian flashing percentage for a batch of shaped abrasive particles.

The percent flashing can be measured by mounting the shaped abrasiveparticle on its side and viewing the body at the side to generate ablack and white image, such as illustrated in FIG. 5C. A suitableprogram for creating and analyzing images, including the calculation ofthe flashing, can be ImageJ software. The percentage flashing can becalculated by determining the area of the body 801 in the boxes 888 and889 compared to the total area of the body as viewed at the side (totalshaded area), including the area in the center 890 and within the boxes888 and 889. Such a procedure can be completed for a suitable samplingof particles to generate average, median, and/or and standard deviationvalues.

A batch of shaped abrasive particles, according to embodiments herein,may exhibit improved dimensional uniformity as measured by the standarddeviation of a dimensional characteristic from a suitable sample size.According to one embodiment, the shaped abrasive particles can have aflashing variation (Vf), which can be calculated as the standarddeviation of flashing percentage (f) for a suitable sample size ofparticles from a batch. According to one embodiment, the flashingvariation can be not greater than about 5.5%, such as not greater thanabout 5.3%, not greater than about 5%, or not greater than about 4.8%,not greater than about 4.6%, or even not greater than about 4.4%. In onenon-limiting embodiment, the flashing variation (Vf) can be at leastabout 0.1%. It will be appreciated that the flashing variation can bewithin a range between any of the minimum and maximum percentages notedabove.

The shaped abrasive particles of the embodiments herein can have aheight (hi) and flashing multiplier value (hiF) of at least 4000,wherein hiF=(hi)(f), an “hi” represents a minimum interior height of thebody as described above and “f” represents the percent flashing. In oneparticular instance, the height and flashing multiplier value (hiF) ofthe body can be greater, such as at least about 4500 micron %, at leastabout 5000 micron %, at least about 6000 micron %, at least about 7000micron %, or even at least about 8000 micron %. Still, in onenon-limiting embodiment, the height and flashing multiplier value can benot greater than about 45000 micron %, such as not greater than about30000 micron %, not greater than about 25000 micron %, not greater thanabout 20000 micron %, or even not greater than about 18000 micron %. Itwill be appreciated that the height and flashing multiplier value of thebody can be within a range between any of the above minimum and maximumvalues. Moreover, it will be appreciated that the above multiplier valuecan be representative of a median multiplier value (MhiF) for a batch ofshaped abrasive particles.

The shaped abrasive particles of the embodiments herein can have adishing (d) and flashing (F) multiplier value (dF) as calculated by theequation dF=(d)(F), wherein dF is not greater than about 90%, “d”represents the dishing value, and “f” represents the percentage flashingof the body. In one particular instance, the dishing (d) and flashing(F) multiplier value (dF) of the body can be not greater than about 70%,such as not greater than about 60%, not greater than about 55%, notgreater than about 48%, not greater than about 46%. Still, in onenon-limiting embodiment, the dishing (d) and flashing (F) multipliervalue (dF) can be at least about 10%, such as at least about 15%, atleast about 20%, at least about 22%, at least about 24%, or even atleast about 26%. It will be appreciated that the dishing (d) andflashing (F) multiplier value (dF) of the body can be within a rangebetween any of the above minimum and maximum values. Moreover, it willbe appreciated that the above multiplier value can be representative ofa median multiplier value (MdF) for a batch of shaped abrasiveparticles.

The shaped abrasive particles of the embodiments herein can have aheight and dishing ratio (hi/d) as calculated by the equationhi/d=(hi)/(d), wherein hi/d is not greater than about 1000, “hi”represents a minimum interior height as described above, and “d”represents the dishing of the body. In one particular instance, theratio (hi/d) of the body can be not greater than about 900 microns, notgreater than about 800 microns, not greater than about 700 microns, oreven not greater than about 650 microns. Still, in one non-limitingembodiment, the ratio (hi/d), can be at least about 10 microns, such asat least about 50 microns, at least about 100 microns, at least about150 microns, at least about 200 microns, at least about 250 microns, oreven at least about 275 microns. It will be appreciated that the ratio(hi/d) of the body can be within a range between any of the aboveminimum and maximum values. Moreover, it will be appreciated that theabove height and dishing ratio can be representative of a median heightand dishing ratio (Mhi/d) for a batch of shaped abrasive particles.

The first bond material can include an inorganic material. In aparticular embodiment, the first bond material can consist essentiallyof an inorganic material. An exemplary inorganic material can include aceramic, a vitreous material, or a combination thereof. Ceramic materialis a composition that includes at least one metal or metalloid element,including but not limited to alkali metal elements, alkaline earth metalelements, lanthanoids, transition metal elements, and a combinationthereof. A particular example of ceramic material may include oxides,carbides, nitrides, borides, and a combination thereof. In anotherembodiment, the first bond material may include a single crystallinephase, a polycrystalline phase, an amorphous phase, or a combinationthereof.

In a further embodiment, the first bond material can include a vitreousmaterial. The vitreous material can have an amorphous phase. Inparticular embodiments, the first bond material may consist essentiallyof vitreous material. In another embodiment, the first bond material caninclude a non-vitreous material. The non-vitreous material may include apolycrystalline phase. In still another embodiment, the first bondmaterial can include a mixture of polycrystalline and vitreous material.

In an embodiment, the first bond material can include oxides includingboron oxide (B₂O₃), silicon oxide (SiO₂), aluminum oxide (Al₂O₃),calcium oxide (CaO), magnesium oxide (MgO), barium oxide (BaO),strontium oxide (SrO), lithium oxide (Li₂O), sodium oxide (Na₂O),potassium oxide (K₂O), cesium oxide (Cs₂O), phosphorous oxide (P₂O₅),zircon, or any combination therefore.

In a further embodiment, the first bond material can include boron oxide(B₂O₃) in a particular content that may facilitate improved formingand/or performance of the abrasive article. Boron oxide can be presentin a certain weight percentage compared to the total weight of the firstbond material. For example, the first bond material may include at most30 wt % of boron oxide (B₂O₃) for the total weight of the first bondmaterial, such as at most 28 wt %, at most 26 wt %, at most 24 wt %, orat most 22 wt % for the total weight of the first bond material. Foranother instance, the first bond material may include at least 2 wt % ofboron oxide for the total weight of the first bond material, such as atleast 3 wt %, at least 4 wt %, at least 5 wt %, at least 6 wt %, atleast 7 wt %, at least 8 wt %, at least 10 wt %, at least 12 wt %, oreven at least 15 wt % for the total weight of the first bond material.It will be understood that the content of boron oxide in the first bondmaterial can be in a range including any minimum to maximum percentagesnoted herein. For example, the first bond material can include a contentof boron oxide in a range of 2 wt % to 30 wt %, in a range of 5 wt % to30 wt %, or in a range of 8 wt % to 22 wt % for the total weight of thefirst bond material.

In an embodiment, the first bond material can include silicon oxide(SiO₂) in a certain content that may facilitate improved forming and/orperformance of the abrasive article. The content of silicon oxiderelative to the total weight of the bond material can be, for example,at most 80 wt %, at most 75 wt %, at most 70 wt %, at most 66 wt %, atmost 65 wt %, at most 63 wt %, at most 60 wt %, at most 55 wt %, at most52 wt %, or at most 50 wt %. In a particular instance, the first bondmaterial can include silicon oxide of less than 66 wt % for the totalweight of the first bond material. In another instance, the first bondmaterial can include at least 25 wt % silicon oxide, such as at least 30wt %, at least 35 wt %, at least 38 wt %, at least 40 wt %, at least 42wt %, at least 45 wt %, at least 47 wt %, at least 48 wt %, or even atleast 49 wt % for the total weight of the first bond material. It willbe appreciated that the content of silicon oxide can be within a rangeincluding any minimum to maximum percentages noted above. For example,the silicon oxide content can be within a range of 35 wt % to 80 wt % orwithin a range of 40 wt % to 65 wt % for the total weight of the firstbond material.

In a further embodiment, the first bond material can include a totalcontent of boron oxide and silicon oxide that may facilitate improvedforming and/or performance of the abrasive article. For instance, thetotal content of boron oxide and silicon oxide may be at most 80 wt %for the total weight of the first bond material, such as at most 77 wt%, at most 75 wt %, at most 73 wt %, at most 70 wt %, at most 70 wt %,or at most 65 wt % for the total weight of the first bond material. Inanother example, the total content of boron oxide and silicon oxide maybe at least 40 wt %, at least 42 wt %, at least 46 wt %, at least 48 wt%, or even at least 50 wt % for the total weight of the first bondmaterial. It will be appreciated that the total content of boron oxideand silicon oxide can be within a range, including any of the minimumand maximum percentages disclosed herein. For example, the total contentof boron oxide and silicon oxide can be within a range from 40 wt % to80 wt % or within a range from 42 wt % to 77 wt % or within a range from46 wt % to 65 wt % for the total weight of the first bond material.

In an embodiment, the first bond material can include a particular ratioof weight percent silicon oxide (SiO₂):weight percent boron oxide (B₂O₃)that may facilitate improved forming and/or performance of the abrasivearticle. For example, the ratio can be at most 22:1, at most 21:1, atmost 20:1, at most 19:1, at most 18:1, at most 16:1, at most 15:1, atmost 12:1, at most 10:1, at most 9:1, at most 8:1, at most 7:1, at most6.5:1, at most 6:1, at most 5.5:1, at most 5.2:1, at most 5:1, or atmost 4.8:1. In another instance, the ratio of weight percent siliconoxide (SiO₂):weight percent boron oxide (B₂O₃) can be at least 1.3:1, atleast 1.5:1, at least 1.7:1, at least 2:1, at least 2.2:1, at least2.4:1, at least 2.6:1, at least 2.8:1, or at least 3:1. It will beappreciated that the ratio of weight percent silicon oxide (SiO₂):weightpercent boron oxide (B₂O₃) can be within a range including any of theminimum and maximum values noted above. For example, the ratio can bewithin a range of 1:3 to 22:1 or within a range of 1:3 to 7:1.

In an embodiment, the first bond material can include aluminum oxide(Al₂O₃) in an amount that can facilitate improved forming and/orperformance of the abrasive article. In an example, the first bondmaterial can include at least 5 wt % aluminum oxide (Al₂O₃) for a totalweight of the bond material, at least 8 wt %, at least 9 wt %, at least10 wt %, at least 12 wt %, or at least 14 wt %. In another example, thefirst bond material can include at most 30 wt % aluminum oxide (Al₂O₃)for a total weight of the bond material, at most 28 wt %, at most 25 wt%, at most 23 wt %, at most 20 wt %, at most 19 wt % or at most 18 wt %for the total weight of the first bond material. It will be appreciatedthat the content of aluminum oxide can be within a range of any of theminimum and maximum percentages noted above. For instance, the firstbond material may include a content of aluminum oxide within a range of5 wt % to 31 wt % or within a range of 10 wt % to 25 wt % for the totalweight of the first bond material.

In an embodiment, the first bond material may include a total content ofaluminum and alumina that can facilitate improved forming and/orimproved performance of the abrasive article. For example, the firstbond material can include a total content of at least 15 wt % of aluminaand aluminum metal (Al₂O₃/Al) for a total weight of the bond material,such as at least 18 wt %, such as at least 20 wt %, at least 22 wt %, oreven at least 24 wt % of alumina and aluminum metal (Al₂O₃/Al) for thetotal weight of the first bond material. In another example, the firstbond material can include at most 45 wt %, such as at most 42 wt %, atmost 40 wt %, at most 38 wt %, at most 35 wt %, or even at most 32 wt %of the total content of alumina and aluminum metal for the total weightof the first bond material. It will be appreciated that the first bondmaterial can include a total content of alumina and aluminum metalwithin a range, including any of the minimum and maximum percentagesnoted herein. For instance, the total content of alumina and aluminummetal can be within a range of 5 wt % to 45 wt % or within a range of 10wt % to 40 wt % or within a range of 22 wt % to 35 wt % for the totalweight of the first bond material.

In an embodiment, the first bond material can include a total content ofaluminum oxide and silicon oxide that may facilitate improved formationand/or performance of the abrasive article. For instance, the totalcontent of aluminum oxide and silicon oxide relative to the total weightof the bond material can be at least 50 wt %, such as at least 52 wt %,at least 56 wt %, at least 58 wt %, or even at least 60 wt %. In anotherexample, the total content of aluminum oxide and silicon oxide can be atmost 80 wt % for the total weight of the first bond material, or at most79 wt %, at most 78 wt %, at most 77 wt %, at most 76 wt %, at most 75wt %, at most 74 wt %, or at most 73 wt % for the total weight of thefirst bond material. It will be appreciated that the total content ofaluminum oxide and silicon oxide can be within a range of any of theminimum to maximum percentages noted herein. For instance, the totalcontent of aluminum oxide and silicon oxide can be within a range of 50wt % to 79 wt %, within a range of 56 wt % to 75 wt %, or even within arange of 60 wt % to 73 wt % for the total weight of the first bondmaterial.

In an embodiment, the first bond material may include a particular ratioof weight percent silicon oxide (SiO₂):weight percent aluminum oxide(Al₂O₃) that can facilitate improved forming and/or improved performanceof the abrasive article. For instance, the ratio can be at most 5.5:1,at most 5:1, at most 4.5:1, at most 4:1, at most 3.5:1, at most 3:1, atmost 2.5:1, at most 2.2:1, or at most 2:1. In another instance, theratio of weight percent silicon oxide (SiO₂):weight percent aluminumoxide (Al₂O₃) can be at least 1.3:1, at least 1.5:1, at least 1.7:1, orat least 2:1. It will be appreciated that the ratio of weight percentsilicon oxide to weight percent aluminum oxide can be within a range,including any of the minimum and maximum ratios noted above. Forexample, the ratio can be within a range of 1:1 to 2.5:1 or within arange of 1.3:1 to 2.2:1.

In an embodiment, the first bond material can include a particularcontent of zircon (ZrSiO₄) that may facilitate the formation of theabrasive article and improve performance. For example, the first bondmaterial may include at least 1 wt % zircon for the total weight of thefirst bond material, such as at least 2 wt %, or at least 3 wt %, or atleast 4 wt %, or at least 5 wt %, or at least 6 wt %, or at least 7 wt%, or at least 8 wt %, or at least 9 wt %, or at least 10 wt %, or atleast 11 wt %, or at least 12 wt %, or at least 13 wt %, or at least 14wt %, or at least 15 wt %, or at least 16 wt %, or at least 17 wt %, orat least 18 wt %, or at least 19 wt %, or at least 20 wt %, or at least21 wt %, or at least 22 wt %, or at least 23 wt %, or at least 24 wt %,or at least 25 wt %, or at least 26 wt %, or at least 27 wt %, or atleast 28 wt %, or at least 29 wt % for the total weight of the firstbond material. In another instance, the first bond material may includeat most 44 wt % zircon, at most 42 wt %, at most 40 wt %, at most 38 wt%, at most 36 wt %, at most 35 wt %, at most 34 wt %, at most 33 wt %,or at most 32 wt % for a total weight of the first bond material. Itwill be appreciated that the first bond material can include a contentof zircon within a range, including any of the minimum and maximumpercentages noted above. In at least one embodiment, the first bondmaterial can be essentially free of zircon (ZrSiO₄).

In an embodiment, the first bond material can include at least onealkaline earth oxide compound (RO) in a content that may facilitateimproved forming and/or performance of the abrasive article. The totalcontent of alkaline earth oxide compounds relative to the total weightof the first bond material may be at most 6 wt %, at most 5 wt %, atmost 4 wt %, at most 3.0 wt %, at most 2.5 wt %, or at most 2 wt %. Inanother embodiment, the total content of alkaline earth oxide compounds(RO) can be at least 0.5 wt % or at least 0.8 wt % for the total weightof the first bond material. It will be appreciated that the totalcontent of alkaline earth oxide compounds (RO) can be within a range,including any of the minimum and maximum percentages noted herein. Forinstance, the total content of alkaline earth oxide compounds (RO) canbe within a range of 0.5 wt % to 5.0 wt % for the total weight of thefirst bond material.

In an embodiment, the first bond material can include at most 3different alkaline earth oxide compounds (RO) from calcium oxide (CaO),magnesium oxide (MgO), barium oxide (BaO), and strontium oxide (SrO).For instance, the first bond material may include at least 0.5 wt %calcium oxide (CaO) for the total weight of the bond material, at least0.8 wt %, or at least 1 wt %. Alternatively, or additionally, the firstbond material may include at most 3 wt % calcium oxide (CaO) for a totalweight of the bond material, at most 2.8 wt %, at most 2.5 wt %, at most2 wt %, or at most 1.7 wt %. Moreover, the content of calcium oxide maybe in a range, including any of the minimum and maximum percentagesnoted herein. In at least one embodiment, the first bond material can beessentially free of calcium oxide (CaO).

In an embodiment, the first bond material can include an alkali oxidecompound (R₂O). Exemplary alkali oxide compounds can include lithiumoxide (Li₂O), sodium oxide (Na₂O), potassium oxide (K₂O), cesium oxide(Cs₂O), or the like. In a further embodiment, the first bond materialcan include at least one alkali oxide compound. Particularly, the firstbond material may include an alkali oxide compound (R₂O) from lithiumoxide (Li₂O), sodium oxide (Na₂O), potassium oxide (K₂O), cesium oxide(Cs₂O), and any combination thereof.

In an embodiment, the total content of the alkali oxide compoundsrelative to the total weight of the first bond material may be at most25 wt %, or at most 22 wt % or at most 20 wt %. Alternatively, oradditionally, the total content of the alkali oxide compounds can be atleast 3 wt %, at least 5 wt %, at least 7 wt %, or at least 9 wt % forthe total weight of the first bond material. It will be appreciated thatthe total content of alkali oxide compounds can be within a range of anyof the minimum to maximum percentages noted herein. For example, thetotal content of alkali oxide compounds can be within a range of 3 wt %to 25 wt % or within a range of 7 wt % to 22 wt % for the total weightof the first bond material.

In an embodiment, the first bond material can include lithium oxide(Li₂O) in an amount that can facilitate improved forming and/orperformance of the abrasive article. For example, the first bondmaterial comprises at least 1 wt % lithium oxide (Li₂O) for the totalweight of the first bond material, at least 1.5 wt % or at least 2 wt %.In another instance, the first bond material can include at most 7 wt %lithium oxide (Li₂O) for the total weight of the bond material, such asat most 6.5 wt %, at most 6 wt %, at most 5.5 wt %, or at most 5 wt %.It will be appreciated that the content of lithium oxide can be within arange of any of the minimum to maximum percentages noted above,including, for example, within a range of 1 wt % to 7 wt % or 1.5 wt %to 6 wt % for the total weight of the first bond material. In at leastone embodiment, the bond material can be essentially free of lithiumoxide (Li₂O).

In an embodiment, the first bond material can include sodium oxide(Na₂O) in an amount that can facilitate improved forming and/orperformance of the abrasive article. The content of sodium oxiderelative to the total weight of the first bond material can be, forexample, at least 3 wt %, at least 4 wt %, or at least 5 wt %. Inanother example, the content of sodium oxide can be at most 15 wt %sodium oxide (Na₂O) for the total weight of the first bond material, atmost 14 wt %, at most 13 wt %, at most 12 wt %, at most 11 wt %, or atmost 10 wt %. It will be appreciated that the content of sodium oxidecan be within a range of any of the minimum to maximum percentages notedabove, including, for example, within a range of 3 wt % to 14 wt % orwithin a range of 4 wt % to 11 wt %.

In an embodiment, the first bond material can include potassium oxide(K₂O) in an amount that can facilitate improved forming and orperformance of the abrasive article. For instance, the content ofpotassium oxide for the total weight of the first bond material can beat least 1 wt %, at least 1.5 wt %, or at least 2 wt %. In anotherinstance, the content of potassium oxide (K₂O) can be at most 15 wt %for the total weight of the first bond material, such as at most 13 wt%, at most 11 wt %, at most 10 wt %, at most 8 wt %, at most 7 wt %, atmost 6.5 wt %, at most 6 wt %, or at most 5.5 wt %, or at most 5 wt %.It will be appreciated that the content of potassium oxide can be withina range of any of the minimum to maximum percentages noted herein,including, for example, within a range of 1 wt % to 15 wt %.

In an embodiment, the first bond material can include phosphorous oxide(P₂O₅) in a content that can facilitate improved forming and/orperformance of the abrasive article. For example, the first bondmaterial can include at most 3.0 wt % phosphorous oxide (P₂O₅) for thetotal weight of the first bond material, such as at most 2 wt % or atmost 1 wt %. In at least one embodiment, the bond material can beessentially free of phosphorus oxide (P₂O₅).

In an embodiment, the first bond material can include a particularcontent of certain components that facilitates suitable formation and/orperformance of the abrasive article. Such components can includemanganese dioxide (MnO₂), iron oxide (Fe₂O₃), ZrSiO₂, CoAl₂O₄, titaniumdioxide (TiO₂), or any combination thereof. For example, in oneinstance, the first bond material can include at most 2 wt % of any oneof manganese dioxide (MnO₂), iron oxide (Fe₂O₃), ZrSiO₂, CoAl₂O₄, ortitanium dioxide (TiO₂) for the total weight of the first bond material,such as at most 1 wt % or even at most 0.5 wt %. In at least oneembodiment, the first bond material can be essentially free of any oneof or combination of manganese dioxide (MnO₂), iron oxide (Fe₂O₃),ZrSiO₂, CoAl₂O₄, or titanium dioxide (TiO₂).

In a particular embodiment, the first bond material may have acomposition including an amount of ceramic particles having a particularparticle size distribution that can facilitate improved performance andproperty of the abrasive articles. In an aspect, the ceramic particlescan have a particular average particle size D50c that can facilitateimproved performance and properties of the abrasive article. The averageparticle size (D50), D10, and D90 of the ceramic particles can bedetermined by using laser diffraction particle size analysis of at least1 g of discrete particles. In an example, the ceramic particles caninclude the average particle size (D50c) of at least 2 microns, at least4 microns, at least 6 microns, at least 7 microns, at least 8 microns,at least 9 microns, at least 10 microns, at least 11 microns, at least12 microns, at least 15 microns, at least 16 microns, at least 17microns, at least 18 microns, at least 19 microns, at least 20 microns,at least 21 microns, at least 22 microns, at least 23 microns, at least24 microns, or at least 25 microns. In another example, the ceramicparticles can include the average particle size (D50c) of at most 35microns, at most 34 microns, at most 33 microns, at most 32 microns, atmost 31 microns, at most 30 microns, at most 29 microns, at most 28microns, at most 27 microns, at most 26 microns, at most 25 microns, atmost 24 microns, at most 23 microns, or at most 22 microns. Moreover,the average particle size of the ceramic particles D50c can be in arange, including any of the minimum and maximum values noted above. Forinstance, the ceramic particles can include the average particle size(D50c) in a range from 2 microns to 35 microns, in a range from 6microns to 30 microns, or in a range from 6 microns to 25 microns.

In another aspect, the ceramic particles may have a particular D10 thatmay define the maximum particle size of the particles in the lowest 10%of the distribution (i.e., the particle size of the abrasive particlesin the 10^(th) percentile of the distribution). For example, the ceramicparticles can include a particle size distribution including a D10 of atleast 1 micron, at least 2 microns, at least 3 microns, at least 5microns, at least 5.5 microns, at least 6 microns, at least 6.5 microns,at least 7 microns, at least 7.5 microns, at least 8 microns, at least8.3 microns, at least 8.5 microns, at least 8.8 microns, at least 9microns, at least 9.2 microns, at least 9.4 microns, at least 9.6microns, at least 9.8 microns, at least 10 microns, at least 10.5microns, at least 10.8 microns, at least 11 microns, at least 11.3microns, at least 11.5 microns, at least 11.8 microns, or at least 12microns. In another example, the ceramic particles can include a D10 ofat most 30 microns, at most 28 microns, at most 27 microns, at most 25microns, at most 23 microns, at most 20 microns, at most 18 microns, atmost 16 microns, at most 14 microns, or at most 13 microns. It will beappreciated that the ceramic particles can have a D10 within a range,including any of the minimum and maximum values noted above.

The ceramic particles may also have a particular D90 that may define theminimum particle size of the particles in the greatest 10% of thedistribution (i.e., the particle size for the abrasive particles in the90^(th) percentile of the distribution). In an example, the ceramicparticles can include D90 of at least 12 microns, at least 15 microns,at least 18 microns, at least 20 microns, at least 22 microns, at least23 microns, at least 24 microns, at least 27 microns, at least 29microns, at least 30 microns, at least 31 microns, at least 33 microns,at least 35 microns, at least 37 microns, at least 38 microns, at least40 microns, at least 41 microns, or at least 42 microns. In anotherexample, the ceramic particles can include D90 of at most 58 microns, atmost 56 microns, at most 54 microns, at most 52 microns, at most 50microns, at most 48 microns, at most 46 microns, at most 45 microns, atmost 44 microns, or at most 43 microns. It will be appreciated that theceramic particles can have a D90 within a range, including any of theminimum and maximum values noted above.

In a further aspect, the ceramic particles can include a crystallinematerial, an amorphous material, or a combination thereof. In aparticular aspect, the ceramic particles can include a polycrystallinematerial having a particular average crystallite size that canfacilitate improved properties and performance of the abrasive articles.For instance, the average crystallite size can be at least 0.005microns, at least 0.01 microns, at least 0.02 microns, at least 0.03microns, at least 0.04 microns, at least 0.05 microns, at least 0.06microns, at least 0.07 microns, at least 0.08 microns, at least 0.09microns, at least 0.1 microns, at least 0.11 microns, at least 0.12microns, at least 0.13 microns, at least 0.14 microns, at least 0.15microns, at least 0.16, at least 0.17 microns, at least 0.18 microns, atleast 0.19 microns, at least 0.2 microns, at least 0.3 microns, at least0.4 microns, at least 0.5 microns, at least 0.6, at least 0.7 microns,at least 0.8 microns, at least 0.9 microns, at least 1 microns, at least1.3 microns, at least 1.5 microns, at least 1.8 microns, at least 2microns, at least 3 microns, at least 4 microns, or at least 5 microns.In another instance, the ceramic particles can include a polycrystallinematerial having an average crystallite size of at most 75 microns, atmost 60 microns, at most 50 microns, at most 40 microns, at most 30microns, at most 20 microns, at most 10 microns, at most 9 microns, atmost 8 microns, at most 7 microns, at most 6 microns, at most 5 microns,at most 4 microns, at most 3 microns, at most 2 microns, at most 1.5microns, at most 1 microns, at most 0.9 microns, at most 0.8 microns, atmost 0.7 microns, at most 0.6 microns, at most 0.5 microns, at most 0.4microns, at most 0.3 microns, at most 0.2 microns, at most 0.1 microns,at most 0.09 microns, at most 0.08 microns, at most 0.07 microns, atmost 0.06 microns, at most 0.05 microns, at most 0.04 microns, at most0.03 microns, at most 0.02 microns, or at most 0.01 microns. Moreover,the ceramic particles can include a polycrystalline material having anaverage crystallite size in a range including any of the minimum andmaximum values noted herein.

In a further aspect, the ceramic particles can include a materialincluding an oxide, a carbide, a nitride, borides, oxycarbides,oxynitrides, silicates, or any combination thereof. In a particularexample, the ceramic particles can include silicon dioxide, siliconcarbide, alumina, zirconia, rare earth-containing materials, ceriumoxide, sol-gel derived particles, iron oxide, glass-containingparticles, and a combination thereof. In another aspect, the ceramicparticles can include the same material as the abrasive particles. Inanother aspect, the ceramic particles can include a different materialthan the abrasive particles. In a particular example, the ceramicparticles can include alumina, such as fused alumina, sol-gel alumina,microcrystalline alumina, nanocrystalline alumina, or any combinationthereof. For instance, ceramic particles can include fused alumina. Inanother instance, the ceramic particles can include white alumina, pinkalumina, or a combination thereof. In a particular implementation, theceramic particles can consist essentially of fused alumina particles. Inan even more particular implementation, the ceramic particles canconsist essentially of white fused alumina. In another particularinstance, the ceramic particles can include alpha-alumina, or moreparticularly, consist essentially of alpha-alumina.

In an aspect, the ceramic particles can include a particular Mohs'shardness that can facilitate improved performance and properties of theabrasive article. For instance, the ceramic particles can include a Mohshardness of at least 5.5, at least 6, at least 6.5, at least 7, at least7.5, at least 8, at least 8.5, or at least 9. In another instance, theceramic particles can include a Mohs' hardness of at most 10, at most9.5, at most 9, at most 8.5, at most 8, at most 7.5, or at most 7.Moreover, the ceramic particles can include a Mohs hardness in a rangeincluding any of the minimum and maximum values noted herein.

In a further aspect, the bond material can include at least 0.0005 wt %of the ceramic particles for the total weight of the bond material, suchas at least 0.0008 wt %, at least 0.001 wt %, at least 0.002 wt %, atleast 0.004 wt %, at least 0.006 wt %, at least 0.008 wt %, at least0.01 wt %, at least 0.02 wt %, at least 0.05 wt %, at least 0.08 wt %,at least 0.1 wt %, at least 0.2 wt %, at least 0.4 wt %, at least 0.5 wt%, at least 0.7 wt %, at least 0.8 wt %, at least 0.9 wt %, at least 1wt %, at least 1.2 wt %, at least 1.4 wt %, at least 1.6 wt %, at least1.8 wt %, at least 2 wt %, at least 2.2 wt %, at least 2.5 wt %, atleast 2.7 wt %, at least 3 wt %, at least 3.3 wt %, at least 3.5 wt %,at least 3.7 wt %, at least 3.9 wt %, at least 4 wt %, at least 4.1 wt%, at least 4.3 wt %, at least 4.5 wt %, at least 4.7 wt %, at least 4.9wt %, at least 5 wt %, at least 6 wt %, at least 7 wt %, at least 9 wt%, at least 10 wt %, at least 12 wt %, at least 15 wt %, at least 17 wt%, at least 19 wt %, at least 20 wt %, at least 22 wt %, at least 25 wt%, at least 28 wt %, or at least 30 wt % for the total weight of thebond material. In another aspect, the content of the ceramic particlescan be less than 50 wt % for the total weight of the bond material, suchas at most 45 wt %, at most 43 wt %, at most 41 wt %, at most 39 wt %,at most 37 wt %, at most 35 wt %, at most 33 wt %, at most 31 wt %, atmost 28 wt %, at most 26 wt %, at most 24 wt %, at most 22 wt %, at most20 wt %, at most 18 wt %, at most 17 wt %, at most 15 wt %, at most 13wt %, at most 11 wt %, at most 10 wt %, at most 9.7 wt %, at most 9.5 wt%, at most 9.4 wt %, at most 9.2 wt %, at most 9 wt %, at most 8.8 wt %,at most 8.6 wt %, at most 8.3 wt %, at most 8 wt %, at most 7.9 wt %, atmost 7.7 wt %, at most 7.5 wt %, at most 7.3 wt %, at most 7 wt %, atmost 6.9 wt %, at most 6.7 wt %, at most 6.6 wt %, at most 6.4 wt %, atmost 6.2 wt %, at most 6 wt %, at most 5.8 wt %, at most 5.6 wt %, atmost 5.4 wt %, at most 5.2 wt %, at most 5 wt %, at most 4.8 wt %, atmost 4.6 wt %, at most 4.1 wt %, at most 3.9 wt %, at most 3.5 wt %, atmost 3.3 wt %, at most 3 wt %, at most 2.7 wt %, at most 2.5 wt %, atmost 2.2 wt %, at most 2 wt %, at most 1.5 wt %, or at most 1 wt % forthe total weight of the bond material. Moreover, the content of theceramic particles can be in a range, including any of the minimum andmaximum percentages noted herein.

A skilled artisan will appreciate the content of the ceramic particlesmay be expressed in volume percent. In an aspect, the content of theceramic particles can be at least 1 vol % for the total volume of thebond material, such as at least 1.3 vol %, at least 1.5 vol %, at least1.8 vol %, at least 2 vol %, at least 2.2%, at least 2.5 vol %, at least2.7 vol %, at least 3 vol %, at least 3.3 vol %, at least 3.5 vol %, atleast 3.7 vol %, at least 3.9 vol %, at least 4 vol %, at least 4.1 vol%, at least 4.3 vol %, at least 4.5 vol %, at least 4.7 vol %, at least4.9 vol %, at least 5 vol %, at least 6 vol %, or at least 7 vol % forthe total volume of the bond material. In another aspect, the content ofthe ceramic particles can be at most 15 vol % for the total volume ofthe bond material, such as at most 12 vol %, at most 11 vol %, at most10 vol %, at most 9.7 vol %, at most 9.5 vol %, at most 9.4 vol %, atmost 9.2 vol %, at most 9 vol %, at most 8.8 vol %, at most 8.6 vol %,at most 8.3 vol %, at most 8 vol %, at most 7.9 vol %, at most 7.7 vol%, at most 7.5 vol %, at most 7.3 vol %, at most 7 vol %, at most 6.9vol %, at most 6.7 vol %, at most 6.6 vol %, at most 6.4 vol %, at most6.2 vol %, at most 6 vol %, at most 5.8 vol %, at most 5.6 vol %, atmost 5.4 vol %, at most 5.2 vol %, at most 5 vol %, at most 4.8 vol %,at most 4.6 vol %, at most 4.3 vol %, or at most 4 vol % for the totalvolume of the bond material. Moreover, the content of the ceramicparticles can be in a range, including any of the minimum and maximumpercentages noted herein.

Referring to FIG. 3A, in an embodiment, the peripheral region 111 of thefirst portion 101 can include the abrasive particles and the bondmaterial noted herein. In an aspect, the peripheral region 111 caninclude a particular content of the first bond material that canfacilitate improved performance of the abrasive article. In an example,the peripheral region 111 can include at least 5 vol % of the first bondmaterial for a total volume of the peripheral region 111, such as atleast 7 vol %, at least 9 vol %, or at least 10 vol %, or at least 11vol %, or at least 12 vol %, or at least 13 vol %, or at least 14 vol %,or at least 15 vol %, or at least 16 vol %, or at least 17 vol %, or atleast 18 vol %, or at least 19 vol %, or at least 20 vol % of the firstbond material for a total volume of the peripheral region. In anotheraspect, the peripheral region 111 can include at most 60 vol % of thefirst bond material for the total volume of the peripheral region 111,such as at most 55 vol %, or at most 50 vol %, or at most 46 vol %, orat most 40 vol %, or at most 35 vol %, or at most 30 vol %, or at most28 vol %, or at most 20 vol %, or at most 15 vol % for the total volumeof the peripheral region 111. Moreover, the peripheral region 111 mayinclude a content of the first bond material in a range, including anyof the minimum and maximum percentages noted herein.

In a further aspect, the first portion 101 of the body 100 may include aparticular content of the bond material that may facilitate the improvedformation of the body and/or improved performance of the abrasivearticle. In an example, the first portion 101 may include at least 5 vol% of the first bond material for the total volume of the first portion101, at least 10 vol %, at least 15 vol %, at least 20 vol %, at least25 vol %, at least 30 vol %, or at least 35 vol % for a total volume ofthe first portion 101. In another example, the first portion may includethe first bond material of at most 60 vol % for the total volume of thefirst portion 101, such as at most 55 vol %, at most 50 vol %, at most45 vol %, at most 40 vol %, at most 35 vol %, or at most 30 vol % forthe total volume of the first portion 101. Moreover, the first portionmay include the content of the first bond material in a range, includingany of the minimum and maximum percentages noted herein.

In an aspect, the peripheral region may include a particular content ofthe first abrasive particles that can facilitate improved performance ofthe abrasive article. In an example, the peripheral region 111 mayinclude the first abrasive particles of at least 5 vol % for the totalvolume of the peripheral region 111, such as at least 10 vol %, or atleast 15 vol %, or at least 20 vol %, or at least 25 vol %, or at least30 vol %, or at least 35 vol % for the total volume of the peripheralregion 111. In another example, the first abrasive portion may includenot greater than 70 vol % the first abrasive particles for the totalvolume of the peripheral region 111, such as not greater than 65 vol %,or not greater than 60 vol %, or not greater than 55 vol %, or notgreater than 50 vol %, or not greater than 45 vol %, or not greater than40 vol %, or not greater than 35 vol %, or not greater than 30 vol %.Moreover, the peripheral region 111 can include a content of the firstabrasive particles in a range including any of the minimum to maximumpercentages noted above. For example, the peripheral region may includea content of the abrasive particles in a range of 5 vol % to 70 vol % orin a range of 15 vol % to 45 vol % for the total volume of theperipheral region.

In a further aspect, the first portion 101 may include having aparticular content of the first abrasive particles that may facilitateimproved formation and performance of the abrasive article. For example,the first portion 101 may include at least 2 vol % of the firstparticles for a total volume of the first portion 101, such as at least5 vol %, or at least 7 vol %, or at least 10 vol %, or at least 15 vol%, or at least 20 vol %, or at least 25 vol %, or at least 30 vol %, orat least 35 vol %, or at least 40 vol %, or at least 42 vol %, or atleast 45 vol % for the total volume of the first portion 101. In anotherexample, the first portion 101 may include at most 70 vol % of the firstabrasive particles for the total volume of the first portion 101, suchas at most 65 vol %, or at most 60 vol %, or at most 55 vol %, or atmost 50 vol %, or at most 45 vol %, or at most 40 vol %, or at most 35vol %, or at most 30 vol % for the total volume of the first portion101. Moreover, the first portion 101 may include a content of the firstabrasive particles within a range, including any of the minimum tomaximum percentages noted herein. For example, the content of the firstabrasive particles may be within a range of 5 vol % to 70 vol % orwithin a range of 15 vol % to 45 vol % for the total volume of the firstportion 101.

In an embodiment, the peripheral region 111 can have porosity. Theporosity can be in various forms. The porosity can extend throughout atleast a portion of the entire volume of the first abrasive portion, andin certain instances, may extend substantially uniformly throughout theentire volume of the first abrasive portion. For instance, the porositycan be closed, open, or include closed porosity and open porosity.Closed porosity can be in the form of discrete pores that are isolatedfrom each other by bond material and/or abrasive particles. Such closedporosity may be formed by pore formers. In other instances, the porositymay be open porosity defining an interconnected network of channelsextending throughout at least a portion of the three-dimensional volumeof the peripheral region 111. In an aspect, the peripheral region 111can include a type of porosity selected from the group consisting ofclosed porosity, open porosity, and a combination thereof. In anotheraspect, the majority of the porosity can include open porosity. In aparticular aspect, all of the porosity can essentially be open porosity.Still, in another aspect, the majority of the porosity can includeclosed porosity. For example, all of the porosity can be essentiallyclosed porosity.

In an embodiment, the peripheral region 111 can have certain porosity tofacilitate improved formation and properties of the abrasive article. Inan aspect, the peripheral region 111 can have a porosity of at least 1vol % for a total volume of the peripheral region, such as at least 5vol % porosity, or at least 10 vol %, or at least 15 vol %, or at least20 vol %, or at least 25 vol %, or at least 30 vol %, or at least 35 vol%, or at least 40 vol %, or at least 45 vol %, or at least 50 vol %, orat least 55 vol %. In another aspect, the peripheral region 111 may haveat most 85 vol % porosity for the total volume of the peripheral region111, such as at most 80 vol %, or at most 70 vol %, or at most 60 vol %,or at most 55 vol %, or at most 50 vol %, or at most 45 vol %, or atmost 40 vol %, or at most 30 vol %. In a further embodiment, theperipheral region 111 can have porosity within a range including any ofthe minimum and maximum percentages noted herein. For example, porositycan be within a range of 0.5 vol % to 85 vol % for a total volume of theperipheral region 111, such as within a range of 30 vol % to 60 vol %.

In another embodiment, the first portion can have certain porosity tofacilitate improved formation and properties of the abrasive article.For example, the first portion can have a porosity of at least 0.5 vol %for the total volume of the first portion, such as at least 1 vol %, atleast 3 vol %, at least 5 vol % porosity or at least 10 vol %, or atleast 15 vol %, or at least 20 vol %, or at least 25 vol %, or at least30 vol %, or at least 35 vol %, or at least 40 vol %, or at least 45 vol%, or at least 50 vol %, or at least 55 vol %. In another example, thefirst portion may have at most 85 vol % porosity for the total volume ofthe first portion, such as at most 80 vol % or at most 70 vol % or atmost 60 vol %, or at most 55 vol %, or at most 50 vol %, or at most 45vol %, or at most 40 vol %, or at most 30 vol %. In a furtherembodiment, the first portion can have a porosity within a rangeincluding any of the minimum and maximum percentages noted herein. Forexample, porosity can be within a range of 1 vol % to 85 vol % for atotal volume of the first portion, such as within a range of 30 vol % to60 vol %.

In an embodiment, the central region 121 may include an inorganicmaterial. In an aspect, the central region 121 may include a vitrifiedmaterial, a crystalline material, or a combination thereof. In a furtheraspect, the central region may include a vitrified material including anoxide-based composition, which may include some content of one or moreof silica, boron oxide, alumina, zircon, sodium oxide, potassium oxide,iron oxide, titanium oxide, magnesium oxide, calcium oxide, and thelike. In another aspect, the central region 121 may include a vitrifiedbond material that is similar or different than the first bond material.In a particular aspect, the central region 121 may consist essentiallyof a vitrified material, a polycrystalline material, an amorphousmaterial, a monocrystalline material, or any combination thereof. Inanother aspect, the central region 121 may consist essentially of avitrified bond material including at least one oxide of silica, boronoxide, alumina, zircon, one or more alkaline earth oxide, one or morealkali oxide, iron oxide, titanium oxide, nickel oxide, and chromiumoxide.

In another particular embodiment, the central region 121 may include aparticular content of a vitrified bond material that can facilitateimproved formation and performance of the abrasive article. In anexample, the central region 121 may include at least 5 wt % of the bondmaterial for a total weight to of the central region 121, such as atleast 8 wt %, at least 9 wt %, at least 10 wt %, at least 11 wt %, atleast 12 wt %, at least 13 wt %, at least 14 wt %, or at least 15 wt %of the bond material for a total weight of the central region 121. Inanother example, the central region 121 may include at most 25 wt % ofthe bond material for a total weight of the central region, such as atmost 22 wt %, at most 20 wt %, at most 18 wt %, at most 15 wt %, or atmost 14 wt % of the bond material for a total weight of the centralregion 121. Moreover, the central region 121 may include a content ofthe bond material in a range including any of the minimum and maximumpercentages noted herein.

In another embodiment, the central region 121 may include abrasiveparticles, one or more filler materials, or any combination thereof. Inan aspect, the central region 121 may include a content of abrasiveparticles, including carbides, nitrides, borides, oxides,superabrasives, or any combination thereof. In another aspect, thecentral region 121 may include abrasive particles, including analumina-based material. For example, abrasive particles may includesintered alumina, fused alumina, microcrystalline alumina, or anycombination thereof. In still another aspect, the central region 121 mayinclude abrasive particles having a particular average particle sizethat can facilitate improved formation and property and/or performanceof the abrasive article. For instance, the central region may includeabrasive particles having an average particle size of at least 40microns, at least 50 microns, at least 60 microns, at least 70 microns,at least 75 microns, at least 80 microns, at least 85 microns, at least90 microns, or at least 95 microns. In another example, the centralregion may include abrasive particles having an average particle size ofat most 140 microns, such as of at most 120 microns, at most 110microns, at most 100 microns, at most 90 microns, at most 85 microns, orat most 80 microns. Moreover, the central region 121 may includeabrasive particles that have an average particle size in a rangeincluding any of the minimum and maximum values noted herein. In anotheraspect, the content of abrasive particles in the central region 121 maybe in a range of 1 vol % to 30 vol % for the total volume of the centralregion 121. In a further aspect, the central region may include a blendof abrasive particles including different materials, average particlesizes, or a combination thereof.

In a particular aspect, the central region 121 may be essentially freeof abrasive particles. Accordingly, the portion of the circumferentialsurface 112 defined by the circumferential surface 141 of the firstportion 101 can be essentially free of abrasive particles.

The content of the abrasive particles may be expressed in weightpercentage. In an example, the central region 121 may include at least60 wt % of abrasive particles for the total weight of the centralregion, such as at least 65 wt %, at least 68 wt %, at least 70 wt %, atleast 72 wt %, at least 75 wt %, at least 77 wt %, at least 80 wt %, atleast 82 wt %, at least 84 wt %, at least 85 wt %, or at least 86 wt %of abrasive particles for the total weight of the central region 121. Inanother example, the central region 121 may include at most 92 wt % ofabrasive particles, such as at most 92 wt %, at most 90 wt %, at most 88wt %, at most 87 wt %, or at most 86 wt % of abrasive particles for thetotal weigh to the central region.

In another aspect, the central region 121 may include one or more fillermaterials including metals, ceramics, vitreous materials, polymers,needle-shaped materials, flakes, granular-shaped materials, fibrousmaterials, or any combination thereof. In a particular embodiment, thefiller material can include at least one of chopped strand fibers, glassfibers, basalt fibers, mineral wool, a metal fiber, a ceramic fiber, acarbon fiber, an aramid fiber, wollastonite, frit, talc, mica,montmorillonite, clay, a pore former, hollow particles, grinding aids,defoamers, or any combination thereof. In another aspect, the centralregion may include a total content of one or more filler materials of atleast 0.5 vol % and at most 30 vol % for the total volume of the centralregion 121. In another aspect, the central region 121 may be essentiallyfree of filler material.

In an embodiment, the central region 121 may include a particularVickers hardness that can facilitate improved properties and performanceof the abrasive article. In an aspect, the central region 121 mayinclude an average Vickers hardness of at least 5.5 GPa, at least 5.7GPa, at least 5.8 GPa, or at least 5.9 GPa. In another aspect, thecentral region 121 can include an average Vickers hardness of at most6.5 GPa, at most 6.4 GPa, or at most 6.3 GPa. It is to be appreciatedthat the central region 121 may include a Vickers hardness in a rangeincluding any of the minimum and maximum values noted herein. Vickershardness is determined according to a standard test method for VickersIndentation Hardness, ASTM C1327-2015.

In another embodiment, the central region 121 may include a Vickershardness greater than Vickers hardness of the peripheral region 111. Forexample, the central region 121 may have a Vickers hardness at least 5%greater than Vickers hardness of the peripheral region 111, such as atleast 10%, at least 20%, at least 30%, at least 40%, at least 50%, or atleast 60% greater than Vickers hardness of the peripheral region 111.Alternatively or additionally, the central region 121 may include aVickers hardness at most 300% greater than the Vickers hardness of theperipheral region 111. In at least one embodiment, the central region121 may include Vickers hardness similar to Vickers hardness of theperipheral region 111. For example, the difference of Vickers hardnessbetween the central region 121 and the peripheral region may be within5% of the Vickers hardness of the peripheral region 111.

In an embodiment, the central region 121 may include porosity. In anaspect, the porosity may consist essentially of closed pores. In anotheraspect, the central region 121 may include porosity of at most 25 vol %of the total volume of the central region 121, such as at most 22 vol %,at most 18 vol %, at most 15 vol %, at most 12 vol %, at most 10 vol %,at most 8 vol %, at most 6 vol %, at most 4 vol %, at most 3 vol %, orat most 1 vol % for the total volume of the central region 121. In stillanother aspect, the central region 121 may include at least 0.5 vol % ofporosity for the total volume of the central region 121, such as atleast 1 vol %, at least 2 vol %, at least 3 vol %, or at least 5 vol %for the total volume of the central region. It will be appreciated thatthe central region 121 may include porosity in a range including any ofthe minimum and maximum percentages noted herein. In a particularaspect, the central region 121 may be essentially free of pores. Inanother particular aspect, the central region 121 may include a porosityin a content less than the content of porosity present in the peripheralregion 111.

Referring to FIG. 3B, a top-down view of the second portion 102 of theabrasive body 100 is illustrated. In an embodiment, the second portion102 can include second abrasive particles contained in the second bondmaterial, including an organic material. The organic material caninclude epoxy, epoxy-based material, epoxy-modified material, or thelike. In a particular embodiment, the second bond material may consistessentially of organic material, including epoxy.

In an embodiment, the second portion 102 may include a particularcontent of the second bond material to facilitate the improved formationof the abrasive article. In an aspect, the second portion 102 mayinclude at least 2 vol % of the second bond material for the totalvolume of the second portion 102, such as at least 5 vol %, at least 10vol %, at least 12 vol %, at least 15 vol %, at least 20 vol %, at least25 vol %, at least 28 vol %, at least 30 vol %, at least 35 vol %, atleast 40 vol %, at least 45 vol %, at least 50 vol %, at least 55 vol %,at least 60 vol %, at least 65 vol %, at least 70 vol % for a totalvolume of the second portion 102. In another example, the second portion102 may include the second bond material of at most 80 vol % for thetotal volume of the second portion 102, such as at most 70 vol %, atmost 65 vol %, at most 60 vol %, at most 55 vol %, at most 52 vol %, atmost 50 vol %, at most 48 vol %, at most 45 vol %, at most 41 vol %, atmost 38 vol %, at most 35 vol %, or at most 30 vol % for a total volumeof the second portion. Moreover, the second bond material may be in acontent in a range including any of the minimum and maximum percentagesnoted herein.

The content of the second bond material may be expressed in weightpercentage relative to the total weight of the second portion 102. In anaspect, the second portion 102 can include the second bond material ofat least 25 wt % for a total weight of the second portion 102, such asat least 30 wt %, at least 32 wt %, at least 35 wt %, at least 38 wt %,at least 40 wt %, at least 42 wt %, at least 44 wt %, or at least 46 wt% for the total weight of the second portion 102. In another aspect, thecontent of the second bond material present in the second portion 102can be at most 52 wt % for the total weight of the second portion 102,such as at most 50 wt %, at most 48 wt %, at most 46 wt %, at most 44 wt%, at most 42 wt %, or at most 40 wt % for the total weight of thesecond portion 102. It will be appreciated that the content of thesecond bond material can be in a range, including any of the minimum andmaximum percentages noted herein.

In a further embodiment, the second portion can include the second bondmaterial that may extend from the inner circumferential surface (e.g.,the surface 142 illustrated in FIG. 1 ) to the outer peripheral surface(e.g., the surface 132 illustrated in FIG. 1 ), wherein one of the innercircumferential surface or the outer peripheral surface may be a worksurface. In a further embodiment, the second portion may include a worksurface including the second bond material and the second abrasiveparticles. In still another embodiment, at least a portion of a worksurface of the body may be defined by the second bond material. Forexample, the second bond material may come into direct contact with awork piece in a material removal operation.

In an embodiment, the second abrasive particles can include a materialincluding an oxide, and in particular, the second abrasive particles caninclude an oxide-based material. In an aspect, the second abrasiveparticles may include a polycrystalline oxide material, includingalumina. For example, the second abrasive particles may includealumina-based abrasive particles, including a crystalline phase,including alpha alumina. In another example, the second abrasiveparticles may include alpha alumina, including an average crystallitesize as described in embodiments in relation to the first abrasiveparticles. In another aspect, the second abrasive particles may includesintered alumina, fused alumina, seeded alumina, microcrystallinealumina, alumina sintered with additives, zirconia-alumina,nanocrystalline alumina, or any combination thereof. For example, thesecond abrasive particles may include fused alumina, sintered alumina,seeded gel alumina, or any combination thereof. In a particular example,the second abrasive particles may consist essentially of seeded gelalumina particles. In another particular example, the second abrasiveparticles may include a blend of abrasive particles, including fusedalumina particles and seeded gel alumina particles. In another example,the second abrasive particles may include at least 90 wt % of aluminafor the total weight of the second abrasive particles, at least 92 wt %,at least 94 wt %, at least 95 wt %, at least 97 wt %, or at least 98.5wt % of alumina for the total weight of the second abrasive particles.

In an embodiment, the second abrasive particles can include a blend ofabrasive particles, including unagglomerated particles, shaped abrasiveparticles, unshaped abrasive particles, elongated abrasive particles,agglomerated particles, or any combination thereof.

In an embodiment, the portion of the circumferential surface 112 definedby the inner circumferential surface 142 of the second portion 102 caninclude the second abrasive particles, the second bond material, or acombination thereof.

In an embodiment, the second portion 102 can include the second abrasiveparticles having a particular average particle size, D_(50AP2), that canfacilitate improved performance of the abrasive article. In an aspect,the second abrasive particles may include an average particle sizeD_(50AP2) of at most 27 microns, at most 25 microns, at most 23 microns,at most 20 microns, at most 19 microns, at most 18 microns, at most 17microns, at most 16 microns, at most 15 microns, at most 14 microns, atmost 13 microns, at most 12 microns, at most 11.5 microns, at most 11microns, at most 10.5 microns, at most 10 microns, at most 9.5 microns,at most 9 microns, at most 9.5 microns, at most 8 microns, at most 7.5microns, at most 7 microns, at most 6.5 microns, at most 6 microns, atmost 5.5 microns, or at most 5 microns. In another aspect, the secondabrasive particles may include an average particle size D_(50AP2) of atleast 2 microns, at least 2.5 microns, at least 3 microns, at least 3.5microns, at least 4 microns, at least 4.5 microns, at least 5 microns,at least 5.5. microns, at least 6 microns, at least 6.5 microns, atleast 7 microns, at least 8 microns, at least 9 microns, at least 10microns, or at least 11 microns. Moreover, the average particle sizeD_(50AP2) may be in a range including any of the minimum and maximumvalues noted herein. For example, the second abrasive particles caninclude an average particle size in a range of at least 2 microns and atmost 27 microns or in a range including at least 4 microns or at most 25microns. In a particular example, the average particle size D_(50AP2) ofthe second abrasive particles may be in a range of 2 microns to 14microns, such as in a range of 2.5 microns to 11 microns. As usedherein, average particle size is intended to refer to the medium valueof particle size distribution, which is the value of the particlediameter at 50% in the cumulative distribution. The average particlesize D50 of the abrasive particles can be determined by utilizing laserdiffraction particle size analysis of at least 1 g of discreteparticles.

In another aspect, the second abrasive particles may have a particularD_(10AP2) that may define the maximum particle size of the particles inthe lowest 10% of the distribution (i.e., the particle size of theabrasive particles in the 10th percentile of the distribution). Forexample, the second abrasive particles can include a particle sizedistribution including a D_(10AP2) of at least 0.5 microns, at least 1micron, at least 2 microns, at least 3 microns, at least 5 microns, atleast 5.5 microns, at least 6 microns, at least 6.5 microns, at least 7microns, at least 7.5 microns, at least 8 microns, at least 8.3 microns,at least 8.5 microns, at least 8.8 microns, at least 9 microns, at least9.2 microns, at least 9.4 microns, at least 9.6 microns, at least 9.8microns, at least 10 microns, at least 10.5 microns, at least 10.8microns, at least 11 microns, at least 11.3 microns, at least 11.5microns, at least 11.8 microns, or at least 12 microns. In anotherexample, the second abrasive particles can include a D_(10AP2) of atmost 7 microns, at most 5 microns, at most 3 microns, or at most 2microns. It will be appreciated that the second abrasive particles canhave a D_(10AP2) within a range, including any of the minimum andmaximum values noted above.

The second particles may also have a particular D_(90AP) that may definethe minimum particle size of the particles in the greatest 10% of thedistribution (i.e., the particle size for the abrasive particles in the90^(th) percentile of the distribution). In an example, the secondabrasive particles can include D_(90AP) of at least 7 microns, at least9 microns, at least 12 microns, at least 15 microns, or at least 18microns. In another example, the second abrasive particles can includeD_(90AP2) of at most 58 microns, at most 56 microns, at most 54 microns,at most 52 microns, at most 50 microns, at most 48 microns, at most 46microns, at most 45 microns, at most 44 microns, at most 43 microns, atmost 40 microns, at most 38 microns, at most 34 microns, at most 31microns, at most 28 microns, at most 25 microns, at most 22 microns, atmost 20 microns, at most 18 microns, or at most 16 microns. It will beappreciated that the second abrasive particles can have a D_(90AP)within a range, including any of the minimum and maximum values notedabove.

In a further embodiment, the second abrasive particles may include aparticular particle distribution measured according to FEPA 42-1:2006.In an aspect, the second abrasive particles may include a particularmedian grain size of D_(s50)-value that may facilitate improvedformation and performance of the abrasive article. For example, thesecond abrasive particles may include D_(s50)-value of at most 15±1.5microns, at most 14.5±1 microns, at most 14±1 microns, at most 13±1microns, at most 12±1 microns, at most 11.5±1 microns, at most 11±1microns, at most 10.5±1 microns, at most 10±1 microns, at most 9.5±1microns, at most 9±1 microns, at most 9.5±1 microns, at most 8±1microns, at most 7.5±1 microns, at most 7±1 microns, at most 6.5±1microns, or at most 6±1 microns. In another example, the second abrasiveparticles may include D_(s50)-value of at least 2.5±0.5 microns, atleast at least 3±0.5 microns, at least 3.5±0.5 microns, at least 4±0.5microns, at least 4.5±1 microns, at least 5±1 microns, at least 5.5±1microns, at least 6±1 microns, or at least 6.5±1 microns. Moreover, thesecond abrasive particles may include D_(s50)-value in a range includingany of the minimum and maximum values noted herein.

In another aspect, the second abrasive particles may include aparticular D_(s94)-value that may facilitate improved formation andperformance of the abrasive article. For example, the second abrasiveparticles may include D_(s94)-value of at most 6.5 microns, at most 6microns, at most 5.5 microns, at most 5 microns, at most 4.5 microns, atmost 4 microns, at most 3.5 microns, at most 3 microns, at most 2.5microns, or at most 2 microns. In another example, the second abrasiveparticles may include D_(s94)-value of at least 0.5 microns, at least 1micron, at least 1.5 microns, at least 2 microns, at least 2.5 microns,or at least 3 microns. Moreover, the second abrasive particles mayinclude D_(s94)-value in a range including any of the minimum andmaximum values noted herein.

In an aspect, the second abrasive particles may include a particularD_(O)-value that may facilitate improved formation and performance ofthe abrasive article. For example, the second abrasive particles mayinclude D_(O)-value of at most 22 microns, at most 20 microns, at most19 microns, at most 18 microns, at most 17 microns, at most 16 microns,at most 15 microns, at most 14 microns, or at most 13 microns. Inanother example, the second abrasive particles may include D_(O)-valueof at least 5.5 microns, at least 6 microns, at least 6.5 microns, atleast 7 microns, at least 8 microns, at least 9 microns, at least 10microns, at least 11 microns, at least 12 microns, at least 13 microns,at least 14 microns, at least 15 microns, or at least 16 microns.Moreover, the second abrasive particles may include D_(O)-value in arange including any of the minimum and maximum values noted herein.

In another embodiment, the second abrasive particles may includeparticles having particle sizes from 0.5 to 25 microns, wherein at most3 wt % for the total weight of the second abrasive particles have theparticle size coarser than 20 micron and at most 6 wt % for the totalweight of the second abrasive particles have the particle size finerthan 1 microns. In a particular example, the second abrasive particlesmay include median grain size of D_(s50)-value in a range including atleast 2.5±0.5 microns and at most 12.5±1 microns, wherein at most 3 wt %of the second abrasive particles have the particle size coarser than 20microns and at most 6 wt % of the second abrasive particles have theparticle size finer than 1 microns.

In a further embodiment, the first and second abrasive particles candiffer in materials, average particle sizes, crystallite sizes, shapes,properties (e.g., hardness and friability), or any combination thereof.In another embodiment, the first and second abrasive particles caninclude the same material but have different shapes, average particlesizes, properties, or any combination thereof. In a particularembodiment, both the first and second abrasive particles can includeabrasive particles, including alumina.

In an embodiment, the second portion 102 can include a certain contentof the second abrasive particles that may facilitate improved formationand properties of the abrasive article. In an aspect, the second portioncan at least 5 vol % of the second abrasive particles for a total volumeof the second portion, such as at least 10 vol %, or at least 15 vol %,or at least 20 vol %, or at least 25 vol %, or at least 30 vol %, or atleast 35 vol %. In another aspect, the second portion may include atmost 90 vol % of the second abrasive particles for the total volume ofthe second portion, such as at most 80 vol %, or at most 70 vol %, or atmost 65 vol %, or at most 60 vol %, or at most 55 vol %, or at most 50vol %, or at most 45 vol %, or at most 40 vol %, or at most 35 vol %, orat most 30 vol %. In a further aspect, the second portion can include acontent of the second abrasive particles within a range, including anyof the minimum and maximum percentages noted herein. For example, thecontent of the second abrasive particles can be within a range of 5 vol% to 90 vol % for the total volume of the second abrasive portion, suchas within a range of 20 vol % to 90 vol %.

The content of the second abrasive particles can be expressed in weightpercentage relative to the total weight of the second portion 102. In anaspect, the second portion 102 may include at least 25 wt % of theabrasive particles for the total weight of the second portion 102, suchas at least 30 wt %, at least 32 wt %, at least 35 wt %, at least 38 wt%, at least 40 wt %, at least 42 wt %, at least 44 wt %, or at least 46wt % for the total weight of the second portion 102. In another aspect,the content of the second abrasive particles present in the secondportion 102 can be at most 75 wt % for the total weight of the secondportion 102, such as at most 70 wt %, at most 65 wt %, at most 63 wt %,at most 60 wt %, at most 58 wt %, at most 57 wt %, or at most 55 wt %for the total weight of the second portion 102. It will be appreciatedthat the content of the second abrasive particles can be in a range,including any of the minimum and maximum percentages noted herein. In aparticular embodiment, the second portion may include the secondabrasive particles in a range from at least 35 wt % and at most 60 wt %,such as in a range including at least 43 wt % and at most 58 wt %, or ina range including at least 47 wt % and at most 57 wt %, or in a rangeincluding at least 52 wt % and at most 57 wt % for the total weight ofthe second portion.

In an embodiment, the body 100 can include a particular average particlesize ratio between the first abrasive particles and the second abrasiveparticles that may facilitate improved performance of the abrasivearticle. In an aspect, the first abrasive particles can have an averageparticles size D_(50AP1) greater than the average particle size of thesecond abrasive particles D_(50AP2) D_(50AP1) is intended to refer tothe average particle size D₅₀ of the first abrasive particles. Whenelongated abrasive particles are present, cross-sectional widths of theelongated abrasive particles are used to determine the average particlesize.

In an embodiment, the body 100 can have a certain ratio,D_(50AP1)/D_(50AP2), of the average particle size of the first portionto the average particle size of the second portion to facilitateimproved formation and properties of the abrasive article. In an aspect,the ratio D_(50AP1)/D_(50AP2) can be greater than 1, such as at least1.2, or at least 1.3, or at least 1.5, or at least 2, or at least 2.5,or at least 3, or at least 3.5, or at least 4, or at least 4.5, or atleast 5, or at least 5.5, or at least 6, or at least 6.5, or at least 7,or at least 7.5, or at least 8, or at least 8.5, or at least 9, or atleast 9.5, or at least 10, or at least 11, or at least 12, or at least15. In another aspect, the ratio D_(50AP1)/D_(50AP2) may be at most 80,such as at most 70, or at most 60, or at most 50, or at most 40, or atmost 38, or at most 35, or at most 30, or at most 20, or at most 18, orat most 15, or at most 12. In a further embodiment, the ratioD_(50AP1)/D_(50AP2) can be within a range including any of the minimumand maximum values noted herein. For instance, the abrasive article canhave the ratio D_(50AP1)/D_(50AP2) within the range including at least1.2 and at most 80 or within a range including at least 2 and at most 70or within a range including at least 3 and not greater than 60.

In one embodiment, the second abrasive particles may include an averageparticle size that is the same as or greater than the average particlesize of the first portion. Accordingly, the body can include a ratio(D_(50AP2)/D_(50AP1)) noted in embodiments in relation to the ratioD_(50AP1)/D_(50AP2).

In an embodiment, the second portion 102 may include a filler material.The filler material can be distinct from the second abrasive particles.An exemplary filler material may be one or more of metals, ceramics,vitreous materials, polymers, needle-shaped materials, flakes,granular-shaped materials, fibrous materials, or any combinationthereof. In a further example, the filler material can include at leastone of chopped strand fibers, basalt fibers, glass fibers, mineral wool,a metal fiber, ceramic fiber, a carbon fiber, an aramid fiber,wollastonite, frit, talc, carbon black, mica, montmorillonite, clay, apore former, hollow particles, grinding aids, defoamers, graphite, orany combination thereof.

In a further embodiment, the second portion 102 may include a fillermaterial in a content of not greater than 25 vol % of the total volumeof the second portion 102, such as at most 20 vol %, at most 15 vol %,at most 12 vol %, at most 10 vol %, or at most 7 vol %. In someapplications, graphite can be present in the second portion for up to 7wt % for the total weight of the second portion, or up to 5 vol % of thetotal volume of the second portion 102. In another aspect, the secondportion 102 can include at least 1 vol % filler for a total volume ofthe second portion 102 or at least 2 vol %, or at least 3 vol %, or atleast 4 vol %, or at least 5 vol %, or at least 6 vol %, or at least 7vol %, or at least 8 vol %, or at least 9 vol %, or at least 10 vol %,or at least 12 vol %, or at least 15 vol %, or at least 20 vol %, or atleast 25 vol %, or at least 30 vol %, or at least 35 vol %. In a furtheraspect, the second portion 102 can include a filler material at acontent within a range, including any of the minimum and maximumpercentages noted herein. In one embodiment, the second portion may beessentially free of filler, such as having a filler content of notgreater than 0.1 vol % for a total volume of the second portion 102.

In an embodiment, the second portion 102 can have porosity in variousforms. For instance, the porosity can be closed, open, or include closedporosity and open porosity. In an aspect, the second portion 102 mayinclude closed porosity, open porosity, or a combination thereof. Inanother aspect, the majority of the porosity can include open porosity.In a particular aspect, all of the porosity can essentially be openporosity. Still, in another aspect, the majority of the porosity caninclude closed porosity. For example, all of the porosity can beessentially closed porosity.

In an embodiment, the second portion 102 may have a certain content ofporosity that may facilitate improved formation and properties of theabrasive article. In an aspect, the second portion 102 can have least 1vol % porosity for a total volume of the second portion 102, such as atleast 3 vol %, or at least 5 vol %, or at least 8 vol %, at least 10 vol%, or at least 12 vol %, or at least 15 vol %, or at least 18 vol %, orat least 20 vol %, or at least 25 vol %, or at least 30 vol %, or atleast 35 vol %. In another aspect, the second portion 102 may have atmost 65 vol % porosity for the total volume of the second portion 102,such as at most 50 vol %, or at most 45 vol %, or at most 40 vol %, orat most 35 vol %, or at most 30 vol %, or at most 25 vol %, or at most20 vol %, or at most 15 vol %, or at most 10 vol %, or at most 8 vol %,or at most 5 vol %, or at most 2 vol %. In still another aspect, thesecond portion 102 can be essentially free of porosity, such as havingat most 0.5 vol % porosity for the total volume of the second portion102. In a further aspect, the second portion 102 can have a content ofporosity within a range, including any of the minimum and maximumpercentages noted herein. For example, the second portion 102 can haveup to 65 vol % of porosity or up to 40 vol % of porosity for the totalvolume of the second portion 102. In another example, the secondabrasive portion can have a content of porosity within a range of 1 vol% to 55 vol % for the total volume of the second portion 102.

In an embodiment, the second portion 102 can include an additive thatcan facilitate improved formation and performance of the abrasivearticle. In an aspect, the additive may include one or more thickeningagents, gelling agents, or any combination thereof. A particular exampleof a suitable additive can include ultra-fine silica. In anotherexample, the additive may include talc, ultra-fine alumina grits,organo-modified silicate, or any combination thereof.

In an embodiment, the second portion may include a particular content ofthe additive that can facilitate improved formation and performance ofthe abrasive article. In an aspect, the second portion 102 can include acontent of silica of at least 0.05 wt % for the total weight of thesecond portion, at least 0.08 wt %, at least 0.1 wt %, at least 0.2 wt%, at least 0.3 wt %, at least 0.4 wt %, at least 0.5 wt %, at least 0.6wt %, at least 0.7 wt %, or at least 0.8 wt %. In another aspect, silicamay be in a content of at most 15 wt %, at most 12 wt %, at most 10 wt%, at most 9 wt %, at most 8 wt %, at most 7 wt %, at most 5 wt %, or atmost 2 wt % for a total weight of the second portion 102. Moreover, thesecond portion 102 may include a content of silica in a range includingany of the minimum or maximum percentages noted herein.

In a further embodiment, the second portion may include silica having anaverage particle size that can facilitate improved formation andperformance of the abrasive particles. In an example, silica may have anaverage particle size D_(50F) of at most 100 nm, such as at most 80 nm,at most 50 nm, at most 30 nm, at most 20 nm, at most 18 nm, at most 15nm, or at most 12 nm. In another example, silica may have an averageparticle size D_(50F) of at least 5 nm, at least 7 nm, at least 9 nm, atleast 11 nm, or at least 12 nm. In a further example, silica may have anaverage particle size D_(50F) in a range including any of the minimumand maximum values noted herein.

In an embodiment, the second portion 102 may include an average particlesize ratio between second abrasive particles and silica. In an aspect,the ratio of D_(50AP2):D_(50F) may be at most 700, at most 600, or atmost 500 or at most 450. In another aspect, the ratio ofD_(50AP2):D_(50F) may be at least 50, at least 60, at least 70, at least85, at least 100, at least 200, at least 300, or at least 400. Moreover,the ratio of D_(50AP2):D_(50F) may be in a range including any of theminimum and maximum values noted herein.

It is noteworthy that the second portion 102 can include an improvedmicrostructure, including a homogenous distribution of the secondabrasive particles throughout the second bond material, improved bondstrength, and improved elasticity, rigidity, and balance therebetween,which facilitates improved performance of the abrasive article. Inparticular, the second portion of embodiments herein demonstrateimproved performance characteristics over a conventional abrasivecounterpart having different compositions, structures, or both. It isfurther notable the second portion 102 has improved properties and/orperformance, including elongation-at-fracture, Young's modulus, and/orModulus of Rupture, which allows the abrasive article of embodimentsherein particularly suitable for operations including precision grindingand other material removal operations.

In an embodiment, the second portion 102 can include an improvedelongation-at-fracture. In an aspect, the second portion 102 can includean elongation-at-fracture of less than 2.7%, such as at most 2.6%, atmost 2.5%, at most 2.4%, or at most 2.3%. In another aspect, the secondportion 102 can include an elongation-at-fracture of at least 1.6%, atleast 1.7, at least 1.8%, at least 1.9%, at least 2.0%, at least 2.1%,at least 2.2%, or at least 2.3%. In a further aspect, the elongation-atfracture of the second abrasive portion 102 may be in a range includingany of the minimum and maximum values noted herein. For example, thesecond portion 102 may include an elongation-at-fracture in a range ofless than 2.7% and at least 1.6%.

Elongation-at-fracture can be determined using a 3-point bending test atroom temperature (i.e., approximately 25° C.) as follows. Bar sampleshaving a dimension of approximately 80 mm×20 mm×15 mm can be cut out ofthe second portion 102. Each bar can be placed on a testing machineknown as 50 kN Pro-Line commercially available from Zwick/Roell oranother functionally equivalent device with the two supporting pinsspaced apart by 7 cm, and a loading force was applied to the middle ofthe bar by the loading pin. The traverse rate can be 10 mm/min, and apre-force of 2 N can be applied. The average of elongation-at-fractureof at least 4 bar samples can be used as elongation-at-fracture of thesecond portion 102.

In a further embodiment, the second portion 102 can include improvedYoung's Modulus. In a further embodiment, the second portion 102 caninclude improved stiffness. In an aspect, the second portion 102 mayinclude a particular Stiffness Value that can facilitate improvedperformance of the abrasive article. In this disclosure, StiffnessValue, V_(YM), may be determined by the formula,V_(YM)=V_(MOR)/(100×V_(EAF)), wherein V_(MOR) refers to Modulus ofRupture (MOR) of the second portion 102, and V_(EAF) refers to theelongation-at-fracture of the second portion 102. MOR can be determinedusing the same 3-point bending test described in relation withelongation-at-fracture. Similarly, MOR of the second portion 102 is theaverage of MOR of at least 4 bar samples.

In an aspect, the second portion can have a Stiffness Value of at least8.3, such as at least 8.5, at least 8.7, at least 8.8, at least 8.9, atleast 9.0, at least 9.1, or at least 9.2. In another aspect, the secondportion can have a Stiffness Value of at most 20, at most 19, at most18, at least 16, at most 14, at most 12, at most 10, or at most 9.5.Moreover, the second portion 102 can have a Stiffness Value in a rangeincluding any of the minimum and maximum values noted herein.

In an embodiment, the second portion may include a particular Modulus ofRupture (MOR) that may facilitate improved performance of the abrasivearticle. In an example, the MOR of the second portion 102 may be atleast 11 MPa, at least 13 MPa, at least 18 MPa, or at least 20 MPa. Inanother example, the second portion may include the MOR of at most 38MPa, at most 35 MPa, at most 33 MPa, at most 30 MPa, at most 28 MPa, orat most 23 MPa. In a further example, the second portion may include anMOR in a range including any of the minimum and maximum values notedherein. For example, the MOR may be in a range of 11 to 38 MPa or in arange of 20 to 25 MPa.

In an embodiment, the second portion can include a particular storagemodulus that can facilitate improved formation and performance of theabrasive article. Storage modulus can be determined by performingDynamical Mechanical Analysis of a sample cut out of the second portion.

In an aspect, the second portion 102 can have a storage modulus at 25°C. of greater than 3130 MPa, such as at least 3200 MPa, at least 3500MPa, at least 3800 MPa, at least 4000 MPa, at least 4200 MPa, or atleast 4500 MPa. In another aspect, the second portion 102 may include astorage modulus at 25° C. of at most 6000 MPa, such as 5800 MPa, at most5500 MPa, at most 5200 MPa, at most 5000 MPa, at most 4900 MPa, at most4700 MPa, at most 4600 MPa, or at most 4500 MPa. In a further aspect,the second portion can include a storage modulus in a range includingany of the minimum and maximum values noted herein. For example, thesecond portion 102 can include a storage modulus at 25° C. in a range ofgreater than 3130 MPa and at most 6000 MPa or in a range of at least4000 MPa and at most 5500 MPa.

It is notable the second portion can maintain a relatively high storagemodulus at elevated temperatures compared to a conventional counterpart.For example, the second portion can 102 have a storage modulus at 50° C.of greater than 2875 MPa, such as at least 3000 MPa, at least 3200 MPa,at least 3300 MPa, at least 3500 MPa, at least 3600 MPa, at least 3700MPa, or at least 3800 MPa. In another example, the second portion 102can include a storage modulus at 50° C. of at most 6000 MPa, at most5800 MPa, at most 5500 MPa, at most 5200 MPa, at most 5000 MPa, at most4800 MPa, at most 4400 MPa, at most 4200 MPa, at most 4000 MPa, or atmost 3800 MPa. In another example, the second portion 102 can include astorage modulus at 50° C. in a range including any of the minimum andmaximum values noted herein. For example, the second portion 102 caninclude a storage modulus at 50° C. in a range of greater than 2875 MPaand at most 6000 MPa or in a range of at least 3200 MPa and at most 5000MPa or in a range of at least 3500 MPa and at most 4500 MPa.

In a further aspect, the second portion can include a particulardecreasing rate of storage modulus over a temperature change that canfacilitate improved formation and performance of the abrasive article.The decreasing rate, R_(DSM) can be determined using the formula,R_(DSM)=(S_(MRT)−S_(MET))/(T_(RT)−T_(ET)), wherein S_(MRT) representsstorage modulus at 25° C. of the second portion 102, S_(MET) representsstorage modulus at an elevated temperature, such as 50° C., of thesecond portion 102, T_(RT)=25, and T_(ET) is the elevated temperature inthe degree Celsius. In an example, the second portion 102 can include adecreasing rate of storage modulus from 25 to 50° C. of greater than10.2 MPa/° C., such as at least 12, at least 15, at least 18, at least20, at least 22, at least 24, at least 26, or at least 28. In anotheraspect, the second portion 102 may include a decreasing rate of storagemodulus from 25 to 50° C. of at most 35, at most 34, at most 32, at most30, at most 29, or at most 28. Moreover, the decreasing rate of storagemodulus from 25 to 50° C. can be in a range including any of the minimumand maximum values noted herein.

In an embodiment, the second portion may include a particularcoefficient of thermal expansion that may facilitate improvedperformance of the abrasive article. In an aspect, the second portionmay have a particular coefficient of thermal expansion in thetemperature range of 30° C. to 50° C. For example, the second portionmay have a coefficient of thermal expansion at 30° C. to 50° C. ofgreater than 33 ppm/° C. or grater than 37 ppm/° C., such as at least37.5 ppm/° C., at least 38 ppm/° C., at least 40 ppm/° C., at least 43ppm/° C., at least 45 ppm/° C., at least 47 ppm/° C., at least 49 ppm/°C., at least 50 ppm/° C., at least 52.5 ppm/° C., at least 54 ppm/° C.,at least 57 ppm/° C., or at least 60 ppm/° C. In another example, thesecond portion may include a coefficient of thermal expansion of lessthan 70 ppm/° C. or less than 69 ppm/° C. In a further example,coefficient of thermal expansion of the second portion may be at most 68ppm/° C., such as at most 66 ppm/° C., at most 64 ppm/° C., at most 61ppm/° C., at most 59 ppm/° C., at most 57 ppm/° C., at most 56 ppm/° C.,at most 55 ppm/° C., or at most 53 ppm/° C. In still a further example,the second portion may include a coefficient of thermal expansion in arange including any of the minimum and maximum values noted herein. Thecoefficient of thermal expansion of the second portion can be determinedas follows. TA Instruments Q400 Thermal Mechanical Analyzer with anExpansion fixture or a device of equivalent function may be usedfollowing ASTM E831.

FIGS. 6A and 6B include an illustration of a process 600 for forming theabrasive article of embodiments herein. As illustrated, the first andsecond portions may be formed separately, and the process 600 can startat either block 601 or 604, as desired, forming a first or secondmixture including abrasive particles and a bond or a precursor bondmaterial. The precursor bond material can form a bond material of afinally formed portion. An exemplary precursor bond material can includea frit, a vitrified material, or a resin.

Referring to block 601, the process 600 can include forming a firstmixture, including the first abrasive particles and the first bondand/or precursor bond material. The bond precursor material may includea powder material that may form the bond material of the finally-formedabrasive article. The bond precursor material can include an inorganicmaterial. In an example, the bond precursor material can include a frit.In another example, the bond precursor material may include a ceramicmaterial. As used herein, a reference to ceramic can include acomposition including at least one metal element and at least onenon-metal element. For example, a ceramic may include material such asoxides, carbides, nitrides, borides, and a combination thereof. Moreparticularly, a ceramic material may have a vitreous phase, crystallinephase, polycrystalline phase, and a combination thereof.

In an embodiment, the bond precursor material can include an oxide-basedcomposition, which may include some content of silica (i.e., silicondioxide), boron oxide, alumina (i.e., aluminum oxide), zircon, sodiumoxide, potassium oxide, iron oxide, titanium oxide, magnesium oxide,calcium oxide, and the like. In some instances, contents of componentsin the bond precursor material may be different from contents ofcomponents in the finally formed body of the abrasive article due toloss on ignition. For instance, the content of component in theprecursor bond material may be calculated by using the formulaC=C_(F)(100%−P_(LOI)), wherein C is the content of a component in thebond precursor, CF is the content of the component in the finally-formedbonded abrasive body, and P_(LOI) is loss of ignition. In furtherinstances, the composition of the bond precursor material and the bondmaterial of the finally-formed bonded abrasive body can be substantiallythe same (i.e., 5% or less difference in any one of the componentsbetween the precursor bond material and bond material of the finallyformed body) or essentially the same (i.e., 1% or less difference in anyone of the components between the precursor bond material and bondmaterial of the finally formed body).

In an embodiment, the first bond/precursor bond material may include theceramic particles.

The first mixture can optionally include one or more filler materials.The filler material may provide improved mechanical properties andfacilitate the formation of the abrasive article.

The filler material can be distinct from the abrasive particles. Forinstance, the filler material may have a hardness less than a hardnessof the abrasive particles. The filler material may also be distinct fromcompositions contained within bond precursor material. In at least oneembodiment, the filler material can include various materials, such asfibers, woven materials, non-woven materials, particles, minerals, nuts,shells, oxides, alumina, carbide, nitrides, borides, organic materials,polymeric materials, naturally occurring materials, and a combinationthereof. In particular instances, the filler material can include amaterial such as wollastonite, mullite, steel, iron, copper, brass,bronze, tin, aluminum, kyanite, alusite, garnet, quartz, fluoride, mica,nepheline syenite, sulfates (e.g., barium sulfate), carbonates (e.g.,calcium carbonate), cryolite, glass, glass fibers, titanates (e.g.,potassium titanate fibers), zircon, rock wool, clay, sepiolite, an ironsulfide (e.g., Fe₂S₃, FeS₂, or a combination thereof), fluorspar (CaF₂),potassium sulfate (K₂SO₄), graphite, potassium fluoroborate (KBF₄),potassium aluminum fluoride (KAlF₄), zinc sulfide (ZnS), zinc borate,borax, boric acid, fine alundum powders, P15A, bubbled alumina, cork,glass spheres, silver, Saran™ resin, paradichlorobenzene, oxalic acid,alkali halides, organic halides, and attapulgite.

Formation of the first mixture can include forming a dry or wet mixture.It may be suitable to create a wet mixture to facilitate homogenousdispersion of the components within the mixture. A skilled artisan willappreciate that the first mixture can include other materials,including, for example, additives, binders, or any other materials knownin the art to facilitate formation of a mixture to create a greenproduct prior to formation of the abrasive article. In at least oneembodiment, the mixture can be essentially free of a pore former. Afterforming the first mixture, the process 600 can continue to block 602,forming the first mixture into a peripheral region. The first mixturemay be processed to form a green body of the peripheral region usingtechniques such as pressing, molding, casting, cutting, printing,curing, depositing, drying, heating, cooling, or any combinationthereof. The green body can be treated subsequently to form a finallyformed peripheral region.

The process 600 can further include forming a mixture including a bondand/or bond precursor material including a frit, vitrified material,ceramic material, or any combination thereof, a binder, and optionally afiller and/or abrasive particles for forming the central region. Themixture may be processed in a similar manner as discussed in relation tothe first mixture to form a green body of the peripheral region 111.

In a particular embodiment, a green body of the first portion may beformed, including the green bodies of the peripheral region and centralregion abutting each other. In an example, one or more shaping devicesmay be used to facilitate the formation of the green body of the firstportion. In a further instance, the process 600 may include forming thegreen body of the peripheral region and forming the green body of thecore region simultaneously. In another example, pressing may beperformed such that green bodies of the peripheral region and centralregion are formed and joined simultaneously. In a particular aspect, theprocess 600 may include pressing to form the green body of the firstportion. In a particular example, pressing can include pressing thefirst mixture and pressing the mixture for the core simultaneously.

In a particular implementation, the first mixture may be poured into afirst compartment of a shaping device, and the mixture for the core maybe poured into a second compartment of the shaping device, wherein thefirst and second compartments may be separated by a removable metalring. Pressing can be performed on both of the mixtures after removingthe metal ring to form the green bodies of the peripheral region and thecore region.

In another example, the green bodies of the peripheral region andcentral region may be formed separately and coupled by subsequenttreatment to form a finally formed first portion. In still anotheraspect, the process 600 may include forming finally formed peripheralregion and central region separately and coupling the finally formedregions.

The green body of the peripheral region, central region, or the firstportion, including the peripheral region and the central region may betreated similarly. Some suitable examples of treating can includeheating, curing, pressing, or a combination thereof. In some instances,a green body may be dried prior to heat treatment. A dryer may be usedto facilitate drying.

An exemplary heating temperature can include at least 700° C., such asat least 750° C., at least 800° C., at least 850° C., or at least 875°C. In an instance, the heating temperature may be at most 1420° C., suchas at most 1300° C., or at most 1250° C. In a further example, theheating temperature can be within a range, including any of the minimumand maximum values disclosed herein. In another example, the heatingtemperature can include the forming temperature of the first bondmaterial. In a further example, the heating temperature may include theforming temperature of the central region. Heating may be performed forat least 2 hours to not greater than 200 hours.

In an embodiment, the vitrified bond material of the core and the firstbond material may have a similar property, including meltingtemperature, forming temperature, wettability, viscosity, flowability,glass transition temperature, the like, or any combination thereof.

In a further embodiment, heating may include bonding the peripheralregion to the core region. In a particular aspect, heating may includesintering the green body of the peripheral region and the green body ofthe core region to form sintered bodies. In a particular example,sintering the green body of the peripheral region and the green body ofthe core region may be performed at the same temperature. In anotheraspect, heating may include directly bonding the peripheral region tothe core region. For example, heating may include forming a sinter-bondbetween the peripheral region and the core region. In an example, thefirst portion may be essentially free of an interface between theperipheral region and the core region. In another example, the firstportion may include an interface between the peripheral region and thecore region, including a composition including a portion of the firstbond material and a portion of the vitrified material of the centralregion.

The process 600 may continue to form the first portion at block 603. Inan aspect, the first portion can be formed after heating treating thegreen body of the first portion. In another aspect, an adhesive may beused to couple the finally formed peripheral region and central regionto form the finally formed first portion.

The process 600 can include, at block 604, forming a second mixtureincluding the second abrasive particles and second bond and/or precursorbond material. The second mixture may optionally include a fillermaterial.

In an embodiment, the second mixture can include a precursor bondmaterial including resins including epoxy resin, modified epoxy resins,epoxy-based resins, or any combination thereof. In an aspect, the resinsmay be non-crystalizing. In another aspect, the resins can have acertain viscosity that can facilitate improved formation of the abrasivearticle. Suitable viscosity can be from 5000 mPa·s to 50000 mPa·s. In aparticular aspect, the epoxy resin may includebisphenole-F-epichlorohydrin resin, bisphenole-A-epichlorohydrin resin,or any combination thereof.

In a further embodiment, the precursor bond material can include one ormore hardeners. An exemplary hardener may include amines, such asdiamines or polyamines, polyamides, cyclic carboxylic acid anhydrides,or any combination thereof. A particular example may include aliphaticamines, such as diethylenetriamine, ethylene diamine;triethylenetetramine or 3,3′,5-trimethylhexamethylenediamine,cycloaliphatic amines, such as 1,2-cyclohexyldiamine, isophoronediamineand its isomer mixtures or m-xylylenediamine; tetraethylenepentamine;2-methyl-1,5-pentamethylenediamine; 1,6-hexamethylenediamine;1,3-pentanediamine; (2-aminoethyl)-1,2-ethanediamine;1,3-pentanediamine; aromatic amines such as methylenedianiline or4,4-diaminodiphenylsulfone; modified amines, such as Mannich bases (forexample diethylene triamine phenol Mannich base) or amine adducts of3,3′,5-trimethylhexamethylenediamine and bisphenol A diglycidyl ether.

The resins and hardener can be mixed in a ratio that can allowstoichiometric reaction and complete polymerization reaction to takeplace. When more than one hardener is used, the ratio between thehardeners can be adjusted to change a property (e.g., elasticity) of thesecond portion as desired by material removal operations.

In an embodiment, the second mixture can include an additive including athickener to facilitate the formation of a uniform dispersion of thesecond mixture. A particular example of a thickener can includeultra-fine silica powder.

In a particular implementation, the resins and one or more hardeners maybe premixed before solid components are added. The mixing ratio of theresins and one or more hardeners may be determined taking intoconsideration of the types and/or contents of functional groups of boththe resins and one or more hardeners. While adding the solid componentsto the liquid premix of the precursor bond material, the mixture can bestirred with low shear force to help avoid the formation of and/or breakagglomerates of abrasive particles and/or other fine particles. Solidcomponents can be slowly added to the liquid mixture to reduce theformation of lumps or agglomerates. Stirring can continue afterfinishing adding all the solid components to the liquid to ensure theformation of a homogenous dispersion of fine particles and viscousprecursor bond material. High shear force may be applied after all thesolid components are added to the mixture.

The process 600 can continue to block 605 after forming the secondmixture, which can include treating the second mixture to form thesecond portion. Treating can include shaping the second mixture in asuitable shaping apparatus, such as a mold having a desired shape. Thesecond mixture can be slowly cast into the mold to help reduce or avoidtrapped air that may result in spallings of the finally formed secondportion. Treating can further include curing the second mixture at aproper temperature to form the organic bonded second portion. Selectionof the curing temperature depends, for instance, on factors such as thetype of bonding material employed, strength, hardness, and grindingperformance desired. In an embodiment, cure can take place in thepresence of heat. In at least one embodiment, curing temperature can bein the range including at least 120° C. to not greater than 250° C. Insome instances, cure can take place at room temperature (from 20° C. to25° C.) in the presence of a proper curing agent, such as utilizingamine or polyamino-amide hardeners to allow certain epoxy resins to cureat room temperature. In some other instances, light can be used to curesuitable resins. Cure can be performed for a period of time. Forexample, the second mixture can be held at a final cure temperature fora period of time, such as between 6 hours and 48 hours, between 10 and24 hours, or until the mixture reaches the cross-linking temperature ordesired density is obtained.

At block 606, the process 600 can include the formation of the body,including the first and second portions, by coupling the portions. In anembodiment, coupling may include applying an adhesive to the firstportion, the second portion, or both to attach the first and secondportions. In an example, a suitable adhesive can include a two-componentepoxy adhesive having a dynamic viscosity of 200000 MPas, density ofabout 1.6 g/cm³, and a vapor pressure of 0.1 hPa at 20° C. The adhesivewas allowed up to 24 hours to cure. The body may be placed in a mold,and the first portion and the second portion may be centered with theaid of magnets.

In another embodiment, the process 600 may include profiling theperipheral surface or circumferential surface of the body to formthreads, geometric features, certain roughness, or the like.

In an embodiment, the center apertures of the first and second portions101 and 102 may be aligned such that the body can have a center aperturethrough the total thickness of the sub-assembly. In a particularembodiment, the first portion 101 and the second portion 102 can beformed such that the center apertures can have the same or similardiameters. In another embodiment, the first and second portions 101 and102 may or may not have the same thickness. In an aspect, the firstportion 101 may have a greater thickness than the second abrasiveportion 102. In another aspect, the first and second portions 101 and102 can have the same or similar thickness. In yet another embodiment,the first 101 and second portions 102 can have the same or similarperimeters.

After forming the body, the body may be incorporated into an abrasivearticle. It will be appreciated that the body may have any suitable sizeand shape as known in the art and can be incorporated into various typesof abrasive articles to form an abrasive article suitable for conductingmaterial removal operations.

In an embodiment, the body 100 can have an average burst speed of atleast 65 m/s to allow the abrasive article to be suitable forapplications requiring a higher grinding speed. For example, the bodycan have an average burst speed of at least 70 m/s, such as at least 75m/s or at least 80 m/s or at least 85 m/s or at least 90 m/s or at least95 m/s or at least 100 m/s or at least 110 m/s or at least 120 m/s or atleast 130 m/s or at least 140 m/s or at least 150 m/s or at least 160m/s or at least 170 m/s or at least 180 m/s. In another embodiment, thebody may have a burst speed of at most 200 m/s or at most 180 m/s or atmost 150 m/s. In a further embodiment, the abrasive article can includea body that has an average speed within a range, including any of theminimum and maximum values disclosed herein. For instance, the body canhave an average burst speed in a range of at least 70 m/s and at most200 m/s, such as in a range of at least 80 m/s and at most 180 m/s.Burst speed, as used herein, refers to the speed limit an abrasivearticle can reach prior to failure and is used to validate the maximumoperational speed permitted by the Organization for the Safety ofAbrasives for using the abrasive article. Burst speed is measured usingthe method published by the Organization for the Safety of Abrasives,which can be found at http://www.osa-abrasives.org/, and in accordancewith EN 12413. The maximum operational speed of an abrasive article mayvary between countries but can be converted from the burst speedfollowing EN 12413. For example, in Europe (EU), conversion can beperformed in accordance with EU ISO EN12413. In the EU, for an openmachine operation, the burst speed of an abrasive article is √3 timesthe maximum operational speed; for a closed machine operation, the bustspeed of an abrasive article is √0.75 times the maximum operationalspeed.

The abrasive articles of embodiments herein have notably improvedperformance. In at least one embodiment, the abrasive articles can haveimproved performance profile holding time, cycle time, power draw,G-Ratio, wear rate, profile retention, and/or material removal ratecompared to a conventional counterpart abrasive article. Improvedperformance of abrasive articles of embodiments herein can befacilitated by one or more of the composition of the first and/or secondbond material, particle sizes, shapes, and/or materials of the firstand/or second abrasive particles, microstructures of the first and/orsecond portions, bonding between the first and second portions, bondingbetween the peripheral region and central region of the first portion,the composition and/or microstructure of the central region, and anycombination thereof.

Many different aspects and embodiments are possible. Some of thoseaspects and embodiments are described herein. After reading thisspecification, skilled artisans will appreciate that those aspects andembodiments are only illustrative and do not limit the scope of thepresent invention. Embodiments may be in accordance with any one or moreof the embodiments as listed below.

Embodiments

Embodiment 1. An abrasive article comprising: a body including: a firstportion comprising first abrasive particles contained within a firstbond material including an inorganic material; a second portioncomprising second abrasive particles contained within a second bondmaterial comprising an organic material comprising epoxy; and a centralopening extending in an axial direction of the body through the firstportion and through the second portion, wherein: the central openingcomprises a circumferential surface defining an inner diameter of thebody, wherein the circumferential surface is defined by at least aportion of the first portion and at least a portion of the secondportion; the second portion is coupled to the first portion in a radialplane; and the second portion comprises an elongation-at-fracture ofless than 2.7%.

Embodiment 2. An abrasive article comprising: a body including: a firstportion comprising first abrasive particles contained within a firstbond material including an inorganic material; a second portioncomprising second abrasive particles contained within a second bondmaterial comprising an organic material comprising epoxy; and a centralopening extending in an axial direction of the body through the firstportion and through the second portion, wherein: the central openingcomprises a circumferential surface defining an inner diameter of thebody, wherein the circumferential surface is defined by at least aportion of the first portion and at least a portion of the secondportion; the second portion is coupled to the first portion in a radialplane; and the second portion comprises a Stiffness Value of at least8.3.

Embodiment 3. The abrasive article of any one of embodiments 1 to 2,wherein the organic material comprises: a storage modulus of greaterthan 3130 MPa at 25° C.; a storage modulus of greater than 2875 MPa at50° C.; or any combination thereof.

Embodiment 4. The abrasive article of any one of embodiments 1 to 3,wherein the second abrasive particles comprise an average particle sizeD_(50AP2) of at most 20 microns, at most 19 microns, at most 18 microns,at most 17 microns, at most 16 microns, at most 15 microns, at most 14microns, at most 13 microns, at most 12 microns, at most 11 microns, atmost 10 microns, at most 9 microns, at most 8 microns, at most 7microns, at most 6 microns, or at most 5 microns.

Embodiment 5. The abrasive article of any one of embodiments 1 to 4,wherein the second abrasive particles comprise an average particle sizeD_(50AP2) of at least 5 microns, at least 6 microns, at least 7 microns,at least 8 microns, at least 9 microns, at least 10 microns, or at least11 microns.

Embodiment 6. The abrasive article of any one of embodiments 1 to 5,wherein the second portion comprises elongation-at-fracture of less than2.7%, such as at most 2.6%, at most 2.5%, at most 2.4%, or at most 2.3%.

Embodiment 7. The abrasive article of any one of embodiments 1 to 6,wherein the second portion comprises elongation-at-fracture of at least1.6%, at least 1.7, at least 1.8%, at least 1.9%, at least 2.0%, atleast 2.1%, at least 2.2%, or at least 2.3%.

Embodiment 8. The abrasive article of any one of embodiments 1 to 7,wherein the second portion comprises Stiffness Value of at least 8.3,such as at least 8.5, at least 8.7, at least 8.8, at least 8.9, at least9.0, at least 9.1, or at least 9.2.

Embodiment 9. The abrasive article of any one of embodiments 1 to 8,wherein the second portion comprises Stiffness Value of at most 20, atmost 19, at most 18, at least 16, at most 14, at most 12, at most 10, orat most 9.5.

Embodiment 10. The abrasive article of any one of embodiments 1 to 9,wherein the second portion comprises Modulus of Rupture of at least 11MPa, at least 13 MPa, at least 18 MPa, or at least 20 MPa.

Embodiment 11. The abrasive article of any one of embodiments 1 to 10,wherein the second portion comprises Modulus of Rupture of at most 38MPa, at most 35 MPa, at most 33 MPa, at most 30 MPa, at most 28 MPa, orat most 23 MPa.

Embodiment 12. The abrasive article of any one of embodiments 1 to 11,wherein the first portion comprises a central region and a peripheralregion coaxial with the central region, wherein the central region has agreater hardness than the peripheral region, a smaller porosity than theperipheral region, or a combination thereof.

Embodiment 13. The abrasive article of embodiment 12, wherein theperipheral region of the first portion comprises an abrasive portioncomprising the first bond material and the first abrasive particles.

Embodiment 14. The abrasive article of embodiment 12 or 13, wherein thebody comprises an outer peripheral surface defining an outer diameter ofthe body, wherein a first portion of the outer peripheral surface of thebody is defined by an outer surface of the peripheral region of thefirst portion.

Embodiment 15. The abrasive article of any one of embodiments 12 to 14,wherein an inner surface of the central region of the first portiondefines a first portion of the circumferential surface of the centralopening, wherein the first portion of the circumferential surface of thecentral opening comprises an inorganic material different than the firstbond material.

Embodiment 16. The abrasive article of any one of embodiments 12 to 15,wherein a second portion of the circumferential surface of the centralopening is defined by an inner surface of the second portion, whereinthe second portion of the circumferential surface comprises the secondbond material, the second abrasive particles, or a combination thereof.

Embodiment 17. The abrasive article of any one of embodiments 12 to 14,wherein the central region of the first portion comprises the first bondmaterial and wherein the first portion of the circumferential surface ofthe central opening comprises the first bond material.

Embodiment 18. The abrasive article of any one of embodiments 12 to 17,wherein the central region of the first portion comprises abrasiveparticles, wherein the first portion of the circumferential surface ofthe central opening comprises the same abrasive particles as the centralregion.

Embodiment 19. The abrasive article of any one of embodiments 12 to 17,wherein the central region of the first portion is essentially free ofabrasive particles, wherein the first portion of the circumferentialsurface is essentially free of abrasive particles.

Embodiment 20. The abrasive article of any one of embodiments 1 to 19,wherein the radial plane extends through the circumferential surface ofthe central opening and an outer peripheral surface of the body.

Embodiment 21. The abrasive article of any one of embodiments 1 to 20,wherein a longitudinal axis extending in an axial direction of the bodyis perpendicular to the radial plane.

Embodiment 22. The abrasive article of any one of embodiments 1 to 21,wherein the first portion and the second portion of the body are onlycoupled in the radial plane.

Embodiment 23. The abrasive article of any one of embodiments 1 to 22,wherein the first portion and the second portion of the body aredirectly bonded to each other.

Embodiment 24. The abrasive article of any one of embodiments 1 to 23,wherein the first portion and the second portion of the body are bondedto each other via an adhesive, wherein the adhesive comprises epoxy,polyurethane, or any combination thereof.

Embodiment 25. The abrasive article of any one of embodiments 1 to 24,wherein an outer peripheral surface of the body comprises surfacefeatures including geometric features, threads, particular roughness, orany combination thereof, wherein the surface features are complementaryto features of a workpiece.

Embodiment 26. The abrasive article of any one of embodiments 1 to 24,wherein a circumferential surface of the central opening comprisessurface features including geometric features, threads, particularroughness, or any combination thereof, wherein the surface features arecomplementary to features of a workpiece.

Embodiment 27. The abrasive article of any one of embodiments 1 to 26,wherein the first bond material comprises a vitrified material.

Embodiment 28. The abrasive article of any one of embodiments 1 to 27,wherein the first abrasive particles comprise agglomerated abrasiveparticles, unagglomerated abrasive particles, shaped abrasive particles,non-shaped abrasive particles, or any combination thereof.

Embodiment 29. The abrasive article of any one of embodiments 1 to 28,wherein at least a portion of the first abrasive particles compriseshaped abrasive particles.

Embodiment 30. The abrasive article of any one of embodiments 1 to 29,wherein the first abrasive particles comprise elongated abrasiveparticles having an average aspect ratio of length to cross-sectionalwidth of at least 2, at least 3, at least 4, or at least 5; or whereinthe average aspect ratio is at most 20, at most 18, at most 15, at most12, at most 10, or at most 8.

Embodiment 31. The abrasive article of any one of embodiments 1 to 30,wherein the first abrasive particles comprises a blend of abrasiveparticles, including elongated abrasive particles and granule abrasiveparticles.

Embodiment 32. The abrasive article of any one of embodiments 1 to 31,wherein the first abrasive particles comprise alumina including seededgel alumina, fused alumina, sol-gel alumina, sol-gel sintered alumina,shaped and sintered alumina, or any combination thereof.

Embodiment 33. The abrasive article of any one of embodiments 1 to 32,wherein the second abrasive particles comprise a polycrystalline oxidematerial.

Embodiment 34. The abrasive article of any one of embodiments 1 to 33,wherein the second abrasive particles comprise an alumina-basedmaterial.

Embodiment 35. The abrasive article of any one of embodiments 1 to 34,wherein the second abrasive particles comprise seeded sol-gel alumina.

Embodiment 36. The abrasive article of any one of embodiments 1 to 35,wherein the second abrasive particles comprise a polycrystalline phaseincluding alpha alumina having an average crystallite size of at most 1micron, at most 0.5 microns, or at most 0.3 microns; or wherein theaverage crystallite size is at least 0.01 microns, at least 0.05microns, at least 0.1 microns, at least 0.14 microns, or at least 0.18microns.

Embodiment 37. The abrasive article of any one of embodiments 1 to 36,wherein the second portion comprises an additive comprising a materialincluding silica, alumina, or any combination thereof, wherein theadditive comprises an average particle size D_(50F) of at most 5microns, at most 2 microns, at most 1 micron, at most 800 nm, at most500 nm, at most 300 nm, at most 200 nm, at most 100 nm, at most 90 nm,at most 80 nm, at most 60 nm, at most 40 nm, at most 30 nm, or at most20 nm; or wherein the average particle size D_(50F) is at least 5 nm, atleast 7 nm, at least 9 nm, at least 10 nm, or at least 12 nm.

Embodiment 38. The abrasive article of embodiment 37, wherein the secondabrasive particles comprise an average particle size D_(50AP2), whereina ratio of D_(50AP2):D_(50F) is at most 700, at most 600, or at most 500or at most 450; or wherein the ratio of D_(50AP2):D_(50F) is at least 2,at least 5, at least 10, at least 50, at least 100, at least 200, atleast 300, or at least 400.

Embodiment 39. The abrasive article of any one of embodiments 1 to 38,wherein the first portion of the body comprises a porosity of at least 5vol %, at least 10 vol %, at least 20 vol %, or at least 30 vol % for atotal volume of the first portion.

Embodiment 40. The abrasive article of any one of embodiments 1 to 39,wherein the first portion of the body comprises a porosity of at most 75vol %, at most 70 vol %, at most 65 vol %, at most 60 vol %, or at most55 vol % for a total volume of the first portion.

Embodiment 41. The abrasive article of any one of embodiments 1 to 40,wherein the first portion of the body comprises the bond material of atleast 5 vol %, at least 10 vol %, at least 15 vol %, at least 20 vol %,at least 25 vol %, at least 30 vol %, or at least 35 vol % for a totalvolume of the first portion.

Embodiment 42. The abrasive article of any one of embodiments 1 to 41,wherein the first portion comprises the bond material of at most 60 vol%, at most 55 vol %, at most 50 vol %, at most 45 vol %, at most 40 vol%, at most 35 vol %, or at most 30 vol % for a total volume of the firstportion.

Embodiment 43. The abrasive article of any one of embodiments 1 to 42,wherein the first portion comprises the first abrasive particles of atleast 10 vol %, at least 15 vol %, at least 20 vol %, at least 30 vol %,at least 35 vol %, or at least 40 vol % or for a total volume of thefirst portion.

Embodiment 44. The abrasive article of any one of embodiments 1 to 43,wherein the first portion comprises the first abrasive particles of atmost 65 vol %, at most 60 vol %, at most 55 vol %, or at most 50 vol %for a total volume of the first portion.

Embodiment 45. The abrasive article of any one of embodiments 1 to 44,wherein the second portion comprises a porosity of at least 3 vol %, atleast 5 vol %, at least 8 vol %, at least 10 vol %, at least 15 vol %,at least 18 vol %, at least 20 vol %, at least 25 vol %, at least 30 vol%, at least 35 vol %, at least 38 vol %, at least 40 vol %, at least 43vol %, or at least 45 vol % for a total volume of the second portion.

Embodiment 46. The abrasive article of any one of embodiments 1 to 45,wherein the second portion comprises a porosity of at most 60 vol %, atmost 57 vol %, at most 55 vol %, at most 50 vol %, or at most 45 vol %for a total volume of the second portion.

Embodiment 47. The abrasive article of any one of embodiments 1 to 46,wherein the second portion comprises the bond material of at least 5 vol%, at least 10 vol %, at least 12 vol %, at least 15 vol %, at least 20vol %, at least 25 vol %, at least 28 vol %, at least 30 vol %, or atleast 35 vol % for a total volume of the second portion.

Embodiment 48. The abrasive article of any one of embodiments 1 to 47,wherein the second portion comprises the bond material of at most 55 vol%, at most 52 vol %, at most 50 vol %, at most 48 vol %, at most 45 vol%, at most 41 vol %, at most 38 vol %, at most 35 vol %, or at most 30vol % for a total volume of the second portion.

Embodiment 49. The abrasive article of any one of embodiments 1 to 48,wherein the second portion comprises the second abrasive particles of atleast 8 vol %, at least 10 vol %, at least 15 vol %, at least 20 vol %,at least 30 vol %, at least 35 vol %, or at least 40 vol % or for atotal volume of the second portion.

Embodiment 50. The abrasive article of any one of embodiments 1 to 49,wherein the second portion comprises the second abrasive particles of atmost 65 vol %, at most 60 vol %, at most 55 vol %, at most 50 vol %, atmost 45 vol %, at most 40 vol %, at most 35 vol %, or at most 30 vol %for a total volume of the second portion.

Embodiment 51. The abrasive article of any one of embodiments 1 to 50,wherein the body comprises an average burst speed of at least 65 m/s, atleast 70 m/s or at least 75 m/s or at least 80 m/s or at least 85 m/s orat least 90 m/s or at least 95 m/s or at least 100 m/s, or at least 110m/s or at least 120 m/s or at least 130 m/s or at least 140 m/s or atleast 150 m/s or at least 160 m/s or at least 170 m/s or at least 180m/s.

Embodiment 52. The abrasive article of any one of embodiments 1 to 51,wherein the body comprises a burst speed of not greater than 200 m/s ornot greater than 180 m/s or not greater than 150 m/s.

Embodiment 53. The abrasive article of any one of embodiments 1 to 52,wherein the second portion comprises an additive including silica,alumina, or any combination thereof, wherein the additive is in anamount of at least 0.05 wt % for the total weight of the second portion,at least 0.08 wt %, at least 0.1 wt %, at least 0.2 wt %, at least 0.3wt %, at least 0.4 wt %, at least 0.5 wt %, at least 0.6 wt %, at least0.7 wt %, or at least 0.8 wt %; or wherein the additive is in an amountof at most 15 wt %, at most 12 wt %, at most 10 wt %, at most 9 wt %, atmost 8 wt %, at most 7 wt %, at most 5 wt %, or at most 2 wt %.

Embodiment 54. The abrasive article of any one of embodiments 1 to 53,wherein the second portion comprises a filler material in an amount ofat most 20 wt % for the total weight of the second portion, at most 18wt %, at most 15 wt %, at most 12 wt %, at most 9 wt %, or at most 6 wt%; or wherein the filler is in an amount of at least 1 wt %, at least 2wt %, at least 3 wt %, at least 4 wt %, or at least 5 wt %.

EXAMPLES Example 1

Abrasive samples representative of the second portions of embodimentsherein were formed according to embodiments herein having thecompositions noted in Table 1 below. The precursor bond material wasprepared by mixing bisphenole-F-epichlorohydrin resins andbisphenole-A-epichlorohydrin resins with amine hardeners. The epoxyresins and hardeners were commercially available from Bakelite® AG. Theabrasive particles, filler material, and ultra-fine silica powder havingthe average particle size of 12 nm were slowly, sequentially added tothe precursor bond material while stirring the mixture at low shearforce. Stirring was continued for 3 to 5 minutes after all the solidcomponents were added or until a homogenous mixture was formed. Highshear forces were applied after all the solid components were added.Ultra-fine silica is added to each mixture in a content from 0.1 wt % to1 wt % for the total weight of the mixture. It is to be understood theapproximate amount (rounded) of each component is included in thisExample, and the total of the content of each component is 100%. Themixture was slowly cast into a mold to help avoid the formation of airbubbles and allowed to cure at room temperature.

MOR and elongation-at-fracture were tested using the 3-point bendingtest described in this disclosure. 4 to 9 samples were formed and testedfor each composition to obtain the average elongation-at-fracture andMOR.

TABLE 1 Average Average Abrasive Abrasive particle Fillers elongation-MOR Samples particles Bond materials/Grit sizes (graphite) at-fractureMPa S1 62 wt % 38 wt % White fused / 1.8% 35.1 alumina/F150 S2 61 wt %34 wt % White fused 5 wt % 1.4% 13.9 alumina/F320 S3 55 wt % 40 wt %White fused 5 wt % 2.3% 21.3 alumina + seeded gel alumina/F800 S4 70 wt% 30 wt % White fused / 1.8% 21.1 alumina/F800 S5 49 wt % 46 wt % Whitefused 5 wt % 2.4% 31.9 alumina/F800

Example 2

A set of 9 samples of Wheel Sample C6 having a polyurethane bond weretested for average elongation-at-fracture and MOR using the same 3-pointbending test described in Example 1. Sample C6 includes approximately 40wt % of the bond material. The average elongation-at-fracture and MOR of9 samples was 2.7% and of 22.2 MPa, respectively.

Example 3

Sample S3 of Example 1 and Sample C6 of Example 2 were tested usingDynamic Mechanical Analysis. FIGS. 7A and 7B include plots of storagemodulus vs. temperatures of Sample S3 of Example 1 and Sample C6 ofExample 2, respectively. At 25° C. and 50° C., Sample S3 of Example 1had a storage modulus of approximately 4500 and 3800 MPa, respectively,while Sample C6 of Example 2 had a storage modulus of 3130 and 2875 MPa,respectively.

Example 4

Abrasive samples S8 and C7 were formed in the same manner as describedin Example 1, except Sample C7 was formed without a thickening agent.The composition of Sample S8 is the same as Sample S3. The content ofsilica was replaced by the bond material for making Sample C7. Sampleswere examined under a scanning electron microscope, and an SEM image ofthe surface of Sample C7 is included in FIG. 8 . Sample C7 includes theabrasive particles 801 and the bond material 802. It is noted Sample C7includes areas 811 to 813 in which less abrasive particles aredistributed, indicating sedimentation of the abrasive particles tookplace. Sample S8 demonstrated uniform distribution of abrasiveparticles.

Example 5

Dual grinding wheels S9 to S12 are formed according to embodimentsherein.

The first portion of wheel Sample S9 includes a peripheral regionincluding a vitrified bond of approximately 20 wt %, TQ grains ofapproximately 40 wt %, and fused alumina particles of approximately 30wt %, and a pore former of approximately 10 wt % for the total weight ofthe peripheral region. TQ grains represent an example of elongated,seeded sol-gel alumina abrasive grains obtained from Saint-GobainAbrasives in Worcester, Mass., and were used in forming all the samples.

The first portion of wheel Sample S10 includes a peripheral regionincluding a vitrified bond of approximately 20 wt %, TQ grains ofapproximately 40 wt %, and fused alumina particles of approximately 30wt %, and approximately 10 wt % of a pore former for the total weight ofthe peripheral region.

The first portion of wheel Sample S11 includes a peripheral regionincluding a vitrified bond of approximately 15 wt %, TQ grains ofapproximately 35 wt %, and agglomerated fused alumina particles ofapproximately 65 wt %, for the total weight of the peripheral region.

The first portion of wheel Sample S12 includes a peripheral regionincluding a vitrified bond of approximately 20 wt % and TQ grains ofapproximately 70 wt % for the total weight of the body and up to 10 wt %of a pore former for the total weight of the peripheral region.

The first portion of wheel Sample S13 includes a peripheral regionincluding a vitrified bond of approximately 15 vol % and agglomeratedruby grains of approximately 85 vol % for the total volume of theperipheral region.

The vitrified bond composition of the peripheral regions of the wheelsamples is included in Table 2 below. The average particle size ofabrasive particles for the peripheral region of each wheel sample isapproximately 100 microns.

The composition of the vitrified bond material of the central region ofeach wheel is similar and similar to the first vitrified bondcomposition included in Table 2. Each core region includes for the totalweight of the core, approximately 80 wt % of fused alumina abrasiveparticles having an average particles size of 60 to 100 microns, and 20wt % of a vitrified bond material.

The second portions of the wheel samples have the same composition asSample S3.

The first portion has the dimension of 275×100×160 mm, and the secondportion has the dimension of 220×60×160 mm. The first portion and thesecond portion are bonded using an epoxy adhesive.

TABLE 2 Component Contents (wt %) SiO₂ 45 to 58 Al₂O₃ 11 to 25 Fe₂O₃  Up to 0.5 TiO₂ Up to 2 CaO Up to 4 MgO Up to 7 Li₂o Up to 4 Na₂O  3 to12 K₂O up to 10 B₂O₃  5 to 20

The dual grinding wheels are tested on grinding and polishing a 20MnCr5workpiece. The dual grinding wheels are expected to perform better thana conventional dual grinding wheel counterpart.

Example 6

Additional abrasive samples were formed according to embodiments hereinhaving the compositions noted in Table 3 below. The precursor bondmaterial was prepared by mixing bisphenole-F-epichlorohydrin resins andbisphenole-A-epichlorohydrin resins with amine hardeners. The epoxyresins and hardeners were commercially available from Bakelite® AG. Theabrasive particles, filler material, and ultra-fine silica powder havingthe average particle size of 12 nm were slowly, sequentially added tothe precursor bond material while stirring the mixture at low shearforce. Stirring was continued for 3 to 5 minutes after all the solidcomponents were added or until a homogenous mixture was formed. Highshear forces were applied after all the solid components were added.Ultra-fine silica is added to each mixture in a content from 0.1 wt % to1 wt % for the total weight of the mixture. It is to be understood theapproximate amount (rounded) of each component is included in thisExample, and the total of the content of each component is 100%. Themixture was slowly cast into a mold to help avoid the formation of airbubbles and allowed to cure at room temperature.

TABLE 3 Abrasive particle CTE at Abrasive Materials/ Fillers 30-50° C.Polishing Samples particles Bond Particle Sizes (graphite) (ppm/° C.)test S11 49 ± 2 wt % 46 ± 2 wt % Fused alumina 5 wt % 52.51 SatisfactoryD50: 6-9 microns; D10: 1-3 microns; D90: 14-17 microns S12 70 ± 2 wt %30 ± 2 wt % Fused alumina / 37.31 Failed D50: 84 microns S13 60 ± 2 wt %30 ± 2 wt % Fused alumina 10 wt % 33.54 Failed D50: 150 microns S14 55 ±2 wt % 40 ± 2 wt % Sol-gel alumina 5 wt % 68.92 Failed D50: 5-8 microns;D10: 1-3 microns; D90: 64-67 microns S15 55 ± 2 wt % 40 wt % Sol-gelalumina 5 wt % 52.83 Satisfactory D50: 6-9 microns; D10: 1-3 microns;D90: 14-17 microns

Polishing tests of Samples S11 to S15 was conducted on 20MnCr5workpieces. Coefficient of thermal expansion (CTE) of the samples weremeasured in accordance with embodiments herein. Thermal expansion ofSamples S11 to S15 are illustrated in FIG. 9 . Samples S11 and S15demonstrated greater expansion compared to Samples S12 and S13 andreduced expansion compared to sample S14 over the temperature range from30° C. to 50° C.

Example 7

Samples S1 to S5 are tested for coefficient of thermal expansion (CTE)in a temperature range from 30 to 50° C. The CTE of Samples S3 and S5are expected to be similar to the CTE of sample 15. The CTE of SamplesS1, S2, and S4 are expected to be adversely affected by the abrasiveparticle sizes, contents of the abrasive particles, or both, and lesssuitable for polishing applications compared to Samples S3, S5, S11, andS15. Polishing tests of samples S1 to S5 are performed on 20MnCr5workpieces. Samples S3 and S5 are expected to have satisfactoryperformance and produce improved surface finish compared to samples S1,S2, and S4.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims. Reference herein to a materialincluding one or more components may be interpreted to include at leastone embodiment wherein the material consists essentially of the one ormore components identified. The term “consisting essentially” will beinterpreted to include a composition including those materialsidentified and excluding all other materials except in minority contents(e.g., impurity contents), which do not significantly alter theproperties of the material. Additionally, or in the alternative, incertain non-limiting embodiments, any of the compositions identifiedherein may be essentially free of materials that are not expresslydisclosed. The embodiments herein include a range of contents forcertain components within a material, and it will be appreciated thatthe contents of the components within a given material total 100%.

The specification and illustrations of the embodiments described hereinare intended to provide a general understanding of the structure of thevarious embodiments. The specification and illustrations are notintended to serve as an exhaustive and comprehensive description of allof the elements and features of apparatus and systems that use thestructures or methods described herein. Separate embodiments may also beprovided in combination in a single embodiment, and conversely, variousfeatures that are, for brevity, described in the context of a singleembodiment, may also be provided separately or in any subcombination.Further, reference to values stated in ranges includes each and everyvalue within that range. Many other embodiments may be apparent toskilled artisans only after reading this specification. Otherembodiments may be used and derived from the disclosure, such that astructural substitution, logical substitution, or another change may bemade without departing from the scope of the disclosure. Accordingly,the disclosure is to be regarded as illustrative rather thanrestrictive.

What is claimed is:
 1. An abrasive article comprising: a body including:a first portion comprising first abrasive particles contained within afirst bond material including an inorganic material; a second portioncomprising second abrasive particles contained within a second bondmaterial comprising an organic material comprising epoxy; and a centralopening extending in an axial direction of the body through the firstportion and through the second portion, wherein: the central openingcomprises a circumferential surface defining an inner diameter of thebody, wherein the circumferential surface is defined by at least aportion of the first portion and at least a portion of the secondportion; the second portion is coupled to the first portion in a radialplane; and the second portion comprises an elongation-at-fracture ofless than 2.7%.
 2. The abrasive article of claim 1, wherein the secondabrasive particles comprise an average particle size D_(50AP2) of atlast 2 microns and at most 20 microns.
 3. The abrasive article of claim2, wherein the second abrasive particles comprise D10 of at least 0.5microns and at most 4 microns, D90 of at least 9 microns and at most 34microns, or both.
 4. The abrasive article of claim 1, wherein the secondabrasive particles are in a content of at least 37 wt % and at most 60wt % for the total weight of the second portion.
 5. The abrasive articleof claim 1, wherein the second portion comprises a coefficient ofthermal expansion of at least 38 ppm/° C. and at most 68 ppm/° C. in atemperature range of 30° C. to 50° C.
 6. The abrasive article of claim1, wherein the second portion comprises the elongation-at-fracture ofless than 2.7% and at least 1.9%.
 7. The abrasive article of claim 1,wherein the radial plane extends through the circumferential surface ofthe central opening and an outer peripheral surface of the body whereina longitudinal axis extending in an axial direction of the body isperpendicular to the radial plane, and wherein the first portion and thesecond portion of the body are only coupled in the radial plane.
 8. Theabrasive article of claim 1, wherein the first bond material comprises avitrified material.
 9. The abrasive article of claim 1, wherein thefirst abrasive particles, the second abrasive particles, or bothcomprise alumina including seeded gel alumina, fused alumina, sol-gelalumina, sol-gel sintered alumina, shaped and sintered alumina, or anycombination thereof.
 10. An abrasive article comprising: a bodyincluding: a first portion comprising first abrasive particles containedwithin a first bond material including an inorganic material; a secondportion comprising second abrasive particles contained within a secondbond material comprising an organic material comprising epoxy; and acentral opening extending in an axial direction of the body through thefirst portion and through the second portion, wherein: the centralopening comprises a circumferential surface defining an inner diameterof the body, wherein the circumferential surface is defined by at leasta portion of the first portion and at least a portion of the secondportion; the second portion is coupled to the first portion in a radialplane; and the second portion comprises a Stiffness Value of at least8.3.
 11. The abrasive article of claim 10, wherein the organic materialcomprises: a storage modulus of greater than 3130 MPa at 25° C.; astorage modulus of greater than 2875 MPa at 50° C.; or any combinationthereof.
 12. The abrasive article of claim 10, wherein the secondabrasive particles comprise an average particle size D_(50AP2) of atlast 2 microns and at most 20 microns.
 13. The abrasive article of claim10, wherein the second abrasive particles comprise D10 of at least 0.5microns and at most 4 microns, D90 of at least 9 microns and at most 34microns, or both.
 14. The abrasive article of claim 10, wherein thesecond portion comprises at least one of the following: a coefficient ofthermal expansion of at least 38 ppm/° C. and at most 68 ppm/° C. in atemperature range of 30° C. to 50° C.; elongation-at-fracture of lessthan 2.7% and at least 1.6%; Stiffness Value of at least 8.3 and at most20; Modulus of Rupture of at least 11 MPa and at most 38 MPa; or anycombination thereof.
 15. The abrasive article of claim 10, wherein thefirst portion comprises a central region and a peripheral region coaxialwith the central region, wherein the central region has a greaterhardness than the peripheral region, a smaller porosity than theperipheral region, or a combination thereof.
 16. The abrasive article ofclaim 15, wherein the peripheral region of the first portion comprisesan abrasive portion comprising the first bond material and the firstabrasive particles.
 17. The abrasive article of claim 15, wherein thebody comprises an outer peripheral surface defining an outer diameter ofthe body, wherein a first portion of the outer peripheral surface of thebody is defined by an outer surface of the peripheral region of thefirst portion.
 18. The abrasive article of claim 15, wherein a secondportion of the circumferential surface of the central opening is definedby an inner surface of the second portion, wherein the second portion ofthe circumferential surface comprises the second bond material, thesecond abrasive particles, or a combination thereof.
 19. The abrasivearticle of claim 10, wherein the first portion of the body comprises fora total volume of the first portion: a porosity of at least 5 vol % andat most 75 vol %; the bond material of at least 5 vol % and at most 60vol %; and the first abrasive particles of at least 10 vol % and at most65 vol %.
 20. The abrasive article of claim 10, wherein the secondportion comprises: a porosity of at least 3 vol % and at most 55 vol %for a total volume of the second portion; the bond material of at least29 wt % and at most 53 wt % for a total weight of the second portion;and the second abrasive particles of at least 37 wt % and at most 60 wt% for the total weight of the second portion.